4GuysFromRolla.com :: Data Source Controls Article Series

Accessing and Updating Data in ASP.NET: Filtering Data Using a CheckBoxList

Wed, 20 Jan 2010 00:00:00 GMT

A Multipart Series on ASP.NET's Data Source Controls

A Multipart Series on ASP.NET's Data Source Controls
ASP.NET 2.0 introduced a number of new Web controls designed for accessing and modifying data. These controls allow page developers to declaratively access and modify data without writing any code to perform the data access. This article is one in a series of articles on ASP.NET's new data source controls. Data Source Control Basics - explores the concepts and advantages of data source controls, and compares their usage in ASP.NET 2.0 to data access techniques in ASP.NET 1.x. Accessing Database Data - shows how to use the SqlDataSource and AccessDataSource controls to query data from a relational database. Filtering Database Data with Parameters - learn how to retrieve just a subset of database data based on hard-coded values and values from the querystring, other Web controls on the page, session variables, and so on. Retrieving XML Data with XmlDataSource Control - see how to retrieve both remote and local XML data and display it in a data Web control. Creating Custom Parameter Controls - learn how to create your own custom, declarative `Parameter` controls for use in the data source controls' parameters collections. Examining the Data Source Control's Events - explore the events raised during a data source control's lifecycle. Declaratively Caching Data - learn how to cache data to the data cache simply by setting a couple of data source control properties. Programmatically Accessing Data using the Data Source Controls - programmatically retrieve, insert, delete, and update data using the SqlDataSource and AccessDataSource controls. Inserting Data - learn how to insert data using a SqlDataSource control. Also examines how to retrieve the `IDENTITY` column value for the just-inserted record. Deleting Data - see how to delete data using a SqlDataSource control. Also looks at how to programmatically cancel a delete. Updating Basics - learn the basics of updating database data using a SqlDataSource control. Also examines using the GridView to provide a web-based editing interface. Customizing the Editing Interface - see how to customize the GridView's columns to provide a customized editing interface that includes input validation and alternative user interface elements. Handling Database NULL Valuese - explore how to extend the GridView's customized editing interface to handle database NULL values. Using Optimistic Concurrency - see how to prevent concurrent users from overwritting one anothers changes by using concurrency control. Filtering Data Using a CheckBoxList - learn how to filter data based on the end user's selections in a CheckBoxList. (Subscribe to this Article Series! )

ASP.NET 2.0 introduced a number of new Web controls designed for accessing and modifying data. These controls allow page developers to declaratively access and modify data without writing any code to perform the data access. This article is one in a series of articles on ASP.NET's new data source controls.

Data Source Control Basics - explores the concepts and advantages of data source controls, and compares their usage in ASP.NET 2.0 to data access techniques in ASP.NET 1.x.

Accessing Database Data - shows how to use the SqlDataSource and AccessDataSource controls to query data from a relational database.

Filtering Database Data with Parameters - learn how to retrieve just a subset of database data based on hard-coded values and values from the querystring, other Web controls on the page, session variables, and so on.

Retrieving XML Data with XmlDataSource Control - see how to retrieve both remote and local XML data and display it in a data Web control.

Creating Custom Parameter Controls - learn how to create your own custom, declarative Parameter controls for use in the data source controls' parameters collections.

Examining the Data Source Control's Events - explore the events raised during a data source control's lifecycle.

Declaratively Caching Data - learn how to cache data to the data cache simply by setting a couple of data source control properties.

Programmatically Accessing Data using the Data Source Controls - programmatically retrieve, insert, delete, and update data using the SqlDataSource and AccessDataSource controls.

Inserting Data - learn how to insert data using a SqlDataSource control. Also examines how to retrieve the IDENTITY column value for the just-inserted record.

Deleting Data - see how to delete data using a SqlDataSource control. Also looks at how to programmatically cancel a delete.

Updating Basics - learn the basics of updating database data using a SqlDataSource control. Also examines using the GridView to provide a web-based editing interface.

Customizing the Editing Interface - see how to customize the GridView's columns to provide a customized editing interface that includes input validation and alternative user interface elements.

Handling Database NULL Valuese - explore how to extend the GridView's customized editing interface to handle database NULL values.

Using Optimistic Concurrency - see how to prevent concurrent users from overwritting one anothers changes by using concurrency control.

Filtering Data Using a CheckBoxList - learn how to filter data based on the end user's selections in a CheckBoxList.

(Subscribe to this Article Series! )

Filtering Database Data with Parameters, an earlier installment in this article series, showed how to filter the data returned by ASP.NET's data source controls. In a nutshell, the data source controls can include parameterized queries whose parameter values are defined via parameter controls. For example, the SqlDataSource can include a parameterized SelectCommand, such as: SELECT * FROM Books WHERE Price > @Price. Here, @Price is a parameter; the value for a parameter can be defined declaratively using a parameter control. ASP.NET offers a variety of parameter controls, including ones that use hard-coded values, ones that retrieve values from the querystring, and ones that retrieve values from session, and others.

Perhaps the most useful parameter control is the ControlParameter, which retrieves its value from a Web control on the page. Using the ControlParameter we can filter the data returned by the data source control based on the end user's input. While the ControlParameter works well with most types of Web controls, it does not work as expected with the CheckBoxList control. The ControlParameter is designed to retrieve a single property value from the specified Web control, but the CheckBoxList control does not have a property that returns all of the values of its selected items in a form that the CheckBoxList control can use. Moreover, if you are using the selected CheckBoxList items to query a database you'll quickly find that SQL does not offer out of the box functionality for filtering results based on a user-supplied list of filter criteria.

The good news is that with a little bit of effort it is possible to filter data based on the end user's selections in a CheckBoxList control. This article starts with a look at how to get SQL to filter data based on a user-supplied, comma-delimited list of values. Next, it shows how to programmatically construct a comma-delimited list that represents the selected CheckBoxList values and pass that list into the SQL query. Finally, we'll explore creating a custom parameter control to handle this logic declaratively. Read on to learn more!

Accessing and Updating Data in ASP.NET: Using Optimistic Concurrency

Wed, 21 May 2008 00:00:00 GMT

A Multipart Series on ASP.NET's Data Source Controls

A Multipart Series on ASP.NET's Data Source Controls
ASP.NET 2.0 introduced a number of new Web controls designed for accessing and modifying data. These controls allow page developers to declaratively access and modify data without writing any code to perform the data access. This article is one in a series of articles on ASP.NET's new data source controls. Data Source Control Basics - explores the concepts and advantages of data source controls, and compares their usage in ASP.NET 2.0 to data access techniques in ASP.NET 1.x. Accessing Database Data - shows how to use the SqlDataSource and AccessDataSource controls to query data from a relational database. Filtering Database Data with Parameters - learn how to retrieve just a subset of database data based on hard-coded values and values from the querystring, other Web controls on the page, session variables, and so on. Retrieving XML Data with XmlDataSource Control - see how to retrieve both remote and local XML data and display it in a data Web control. Creating Custom Parameter Controls - learn how to create your own custom, declarative `Parameter` controls for use in the data source controls' parameters collections. Examining the Data Source Control's Events - explore the events raised during a data source control's lifecycle. Declaratively Caching Data - learn how to cache data to the data cache simply by setting a couple of data source control properties. Programmatically Accessing Data using the Data Source Controls - programmatically retrieve, insert, delete, and update data using the SqlDataSource and AccessDataSource controls. Inserting Data - learn how to insert data using a SqlDataSource control. Also examines how to retrieve the `IDENTITY` column value for the just-inserted record. Deleting Data - see how to delete data using a SqlDataSource control. Also looks at how to programmatically cancel a delete. Updating Basics - learn the basics of updating database data using a SqlDataSource control. Also examines using the GridView to provide a web-based editing interface. Customizing the Editing Interface - see how to customize the GridView's columns to provide a customized editing interface that includes input validation and alternative user interface elements. Handling Database NULL Valuese - explore how to extend the GridView's customized editing interface to handle database NULL values. Using Optimistic Concurrency - see how to prevent concurrent users from overwritting one anothers changes by using concurrency control. (Subscribe to this Article Series! )

Data Source Control Basics - explores the concepts and advantages of data source controls, and compares their usage in ASP.NET 2.0 to data access techniques in ASP.NET 1.x.

Accessing Database Data - shows how to use the SqlDataSource and AccessDataSource controls to query data from a relational database.

Retrieving XML Data with XmlDataSource Control - see how to retrieve both remote and local XML data and display it in a data Web control.

Creating Custom Parameter Controls - learn how to create your own custom, declarative Parameter controls for use in the data source controls' parameters collections.

Examining the Data Source Control's Events - explore the events raised during a data source control's lifecycle.

Declaratively Caching Data - learn how to cache data to the data cache simply by setting a couple of data source control properties.

Programmatically Accessing Data using the Data Source Controls - programmatically retrieve, insert, delete, and update data using the SqlDataSource and AccessDataSource controls.

Inserting Data - learn how to insert data using a SqlDataSource control. Also examines how to retrieve the IDENTITY column value for the just-inserted record.

Deleting Data - see how to delete data using a SqlDataSource control. Also looks at how to programmatically cancel a delete.

Updating Basics - learn the basics of updating database data using a SqlDataSource control. Also examines using the GridView to provide a web-based editing interface.

Customizing the Editing Interface - see how to customize the GridView's columns to provide a customized editing interface that includes input validation and alternative user interface elements.

Handling Database NULL Valuese - explore how to extend the GridView's customized editing interface to handle database NULL values.

Using Optimistic Concurrency - see how to prevent concurrent users from overwritting one anothers changes by using concurrency control.

(Subscribe to this Article Series! )

Because multiple users can visit the same web page concurrently, it is possible for a user visiting a data modification page to inadvertently overwrite the modifications made by another user. Consider a page with an editable GridView. If two users visit this page simultaneously from different computers and both edit the same row, whomever saves the first will have her changes overwritten by whomever saves the row last. This type of behavior is known as "last write wins" and is the default behavior for web applications.

"Last write wins" is sufficient in applications where it is very rare for two users to be simultaneously working on the same data. If it is commonplace for multiple users to be modifying the same set of data, you should consider implementing some form of concurrency control. There are two flavors of concurrency control: optimistic and pessimistic. Optimistic assumes that concurrency violations are rare and that if such an error occurs that it's adequate to ask one of the conflicting parties to re-enter their information. Pessimistic concurrency, on the other hand, implements policies to ensure that concurrency violations cannot occur. These policies may add friction to the end user's data entry experience.

Microsoft offers a form of optimistic concurrency control from the SqlDataSource control that can be enabled by ticking a checkbox. This article looks at different types of concurrency control and then shows how to implement the built-in optimistic concurrency control offered by the SqlDataSource control. Read on to learn more!

Accessing and Updating Data in ASP.NET: Handling Database NULL Values

mitchell@4guysfromrolla.com (Scott Mitchell) — Wed, 28 Nov 2007 00:00:00 GMT

A Multipart Series on ASP.NET's Data Source Controls

A Multipart Series on ASP.NET's Data Source Controls
ASP.NET 2.0 introduced a number of new Web controls designed for accessing and modifying data. These controls allow page developers to declaratively access and modify data without writing any code to perform the data access. This article is one in a series of articles on ASP.NET's new data source controls. Data Source Control Basics - explores the concepts and advantages of data source controls, and compares their usage in ASP.NET 2.0 to data access techniques in ASP.NET 1.x. Accessing Database Data - shows how to use the SqlDataSource and AccessDataSource controls to query data from a relational database. Filtering Database Data with Parameters - learn how to retrieve just a subset of database data based on hard-coded values and values from the querystring, other Web controls on the page, session variables, and so on. Retrieving XML Data with XmlDataSource Control - see how to retrieve both remote and local XML data and display it in a data Web control. Creating Custom Parameter Controls - learn how to create your own custom, declarative `Parameter` controls for use in the data source controls' parameters collections. Examining the Data Source Control's Events - explore the events raised during a data source control's lifecycle. Declaratively Caching Data - learn how to cache data to the data cache simply by setting a couple of data source control properties. Programmatically Accessing Data using the Data Source Controls - programmatically retrieve, insert, delete, and update data using the SqlDataSource and AccessDataSource controls. Inserting Data - learn how to insert data using a SqlDataSource control. Also examines how to retrieve the `IDENTITY` column value for the just-inserted record. Deleting Data - see how to delete data using a SqlDataSource control. Also looks at how to programmatically cancel a delete. Updating Basics - learn the basics of updating database data using a SqlDataSource control. Also examines using the GridView to provide a web-based editing interface. Customizing the Editing Interface - see how to customize the GridView's columns to provide a customized editing interface that includes input validation and alternative user interface elements. Handling Database NULL Valuese - explore how to extend the GridView's customized editing interface to handle database NULL values. (Subscribe to this Article Series! )

Data Source Control Basics - explores the concepts and advantages of data source controls, and compares their usage in ASP.NET 2.0 to data access techniques in ASP.NET 1.x.

Accessing Database Data - shows how to use the SqlDataSource and AccessDataSource controls to query data from a relational database.

Retrieving XML Data with XmlDataSource Control - see how to retrieve both remote and local XML data and display it in a data Web control.

Creating Custom Parameter Controls - learn how to create your own custom, declarative Parameter controls for use in the data source controls' parameters collections.

Examining the Data Source Control's Events - explore the events raised during a data source control's lifecycle.

Declaratively Caching Data - learn how to cache data to the data cache simply by setting a couple of data source control properties.

Programmatically Accessing Data using the Data Source Controls - programmatically retrieve, insert, delete, and update data using the SqlDataSource and AccessDataSource controls.

Inserting Data - learn how to insert data using a SqlDataSource control. Also examines how to retrieve the IDENTITY column value for the just-inserted record.

Deleting Data - see how to delete data using a SqlDataSource control. Also looks at how to programmatically cancel a delete.

Updating Basics - learn the basics of updating database data using a SqlDataSource control. Also examines using the GridView to provide a web-based editing interface.

Customizing the Editing Interface - see how to customize the GridView's columns to provide a customized editing interface that includes input validation and alternative user interface elements.

Handling Database NULL Valuese - explore how to extend the GridView's customized editing interface to handle database NULL values.

(Subscribe to this Article Series! )

In the last two installments of this article series - Updating Basics and Customizing the Editing Interface - we saw how to configure the SqlDataSource control to issue UPDATE statements to a database and how to then configure the GridView control to work in tandem with the SqlDataSource control to provide a web-based editing interface. By default, the GridView's editing interface renders a TextBox for each editable column in the grid. However, in certain scenarios we may want to customize the editing interface by including validation controls or by using an alternative Web control to collect the user's input. In particular, we customized the editing interface so that when editing a product from the Northwind database, a user could select the product's category through a DropDownList control rather than having to enter the actual CategoryID value into a TextBox.

While the Customizing the Editing Interface article provided a complete, working example of creating a customized editing interface, it had one potentially criticial shortcoming - the approach did not work with products that had a NULL database value for their CategoryID. For starters, the SELECT query used to populate the GridView used an INNER JOIN, which only returned those products with a matching category record. But even if we update the query to use a LEFT JOIN, the DropDownList in the customized editing interface did not include a list item representing the NULL value, so a user would be unable to edit a product and change the category from an existing value to NULL.

In this article we will look at how to customize the DropDownList in the editing interface such that it can correctly handle database NULL values. Read on to learn more!

Accessing and Updating Data in ASP.NET: Customizing the Editing Interface

mitchell@4guysfromrolla.com (Scott Mitchell) — Wed, 08 Aug 2007 00:00:00 GMT

A Multipart Series on ASP.NET's Data Source Controls

A Multipart Series on ASP.NET's Data Source Controls
ASP.NET 2.0 introduced a number of new Web controls designed for accessing and modifying data. These controls allow page developers to declaratively access and modify data without writing any code to perform the data access. This article is one in a series of articles on ASP.NET's new data source controls. Data Source Control Basics - explores the concepts and advantages of data source controls, and compares their usage in ASP.NET 2.0 to data access techniques in ASP.NET 1.x. Accessing Database Data - shows how to use the SqlDataSource and AccessDataSource controls to query data from a relational database. Filtering Database Data with Parameters - learn how to retrieve just a subset of database data based on hard-coded values and values from the querystring, other Web controls on the page, session variables, and so on. Retrieving XML Data with XmlDataSource Control - see how to retrieve both remote and local XML data and display it in a data Web control. Creating Custom Parameter Controls - learn how to create your own custom, declarative `Parameter` controls for use in the data source controls' parameters collections. Examining the Data Source Control's Events - explore the events raised during a data source control's lifecycle. Declaratively Caching Data - learn how to cache data to the data cache simply by setting a couple of data source control properties. Programmatically Accessing Data using the Data Source Controls - programmatically retrieve, insert, delete, and update data using the SqlDataSource and AccessDataSource controls. Inserting Data - learn how to insert data using a SqlDataSource control. Also examines how to retrieve the `IDENTITY` column value for the just-inserted record. Deleting Data - see how to delete data using a SqlDataSource control. Also looks at how to programmatically cancel a delete. Updating Basics - learn the basics of updating database data using a SqlDataSource control. Also examines using the GridView to provide a web-based editing interface. Customizing the Editing Interface - see how to customize the GridView's columns to provide a customized editing interface that includes input validation and alternative user interface elements. (Subscribe to this Article Series! )

Data Source Control Basics - explores the concepts and advantages of data source controls, and compares their usage in ASP.NET 2.0 to data access techniques in ASP.NET 1.x.

Accessing Database Data - shows how to use the SqlDataSource and AccessDataSource controls to query data from a relational database.

Retrieving XML Data with XmlDataSource Control - see how to retrieve both remote and local XML data and display it in a data Web control.

Creating Custom Parameter Controls - learn how to create your own custom, declarative Parameter controls for use in the data source controls' parameters collections.

Examining the Data Source Control's Events - explore the events raised during a data source control's lifecycle.

Declaratively Caching Data - learn how to cache data to the data cache simply by setting a couple of data source control properties.

Programmatically Accessing Data using the Data Source Controls - programmatically retrieve, insert, delete, and update data using the SqlDataSource and AccessDataSource controls.

Inserting Data - learn how to insert data using a SqlDataSource control. Also examines how to retrieve the IDENTITY column value for the just-inserted record.

Deleting Data - see how to delete data using a SqlDataSource control. Also looks at how to programmatically cancel a delete.

Updating Basics - learn the basics of updating database data using a SqlDataSource control. Also examines using the GridView to provide a web-based editing interface.

Customizing the Editing Interface - see how to customize the GridView's columns to provide a customized editing interface that includes input validation and alternative user interface elements.

(Subscribe to this Article Series! )

In the last installment of this article series, Updating Basics, we looked at how to configure the SqlDataSource control to issue UPDATE statements to a database. We then saw how the GridView control can work in tandem with the SqlDataSource control to provide a simple web-based editing interface composed of textboxes for each data field. While this simplified interface enabled developers to create an editable interface with zero code and just a few clicks of the mouse, the interface is so simple that it is impractical for all but the most trivial scenarios. Some of these limitations were exhibited in the Updating Basics article when attempting to update a product's Category. In short, you had to modify the product's CategoryID value, meaning that to change a product's category from Beverages to Dairy you would have to change the CategoryID value from 1 to 4. Likewise, the simplified interface lacks any input validation that may be necessary when editing required fields or fields that must appear in a particular format (like dates or numbers).

Fortunately, the GridView's editing interface can be customized to include validation controls and alternative user interface elements. It requires a little more effort, but in most cases these changes can be completed entirely through the Designer or the page's declarative markup. In this installment we will extend the simplified editing interface from Updating Basics to include validation controls for the ProductName and UnitPrice fields; we will also replace the CategoryID data field's textbox with a drop-down list that enumerates the possible categories. Read on to learn more!

Accessing and Updating Data in ASP.NET: Updating Basics

mitchell@4guysfromrolla.com (Scott Mitchell) — Wed, 01 Aug 2007 00:00:00 GMT

A Multipart Series on ASP.NET's Data Source Controls

A Multipart Series on ASP.NET's Data Source Controls
ASP.NET 2.0 introduced a number of new Web controls designed for accessing and modifying data. These controls allow page developers to declaratively access and modify data without writing any code to perform the data access. This article is one in a series of articles on ASP.NET's new data source controls. Data Source Control Basics - explores the concepts and advantages of data source controls, and compares their usage in ASP.NET 2.0 to data access techniques in ASP.NET 1.x. Accessing Database Data - shows how to use the SqlDataSource and AccessDataSource controls to query data from a relational database. Filtering Database Data with Parameters - learn how to retrieve just a subset of database data based on hard-coded values and values from the querystring, other Web controls on the page, session variables, and so on. Retrieving XML Data with XmlDataSource Control - see how to retrieve both remote and local XML data and display it in a data Web control. Creating Custom Parameter Controls - learn how to create your own custom, declarative `Parameter` controls for use in the data source controls' parameters collections. Examining the Data Source Control's Events - explore the events raised during a data source control's lifecycle. Declaratively Caching Data - learn how to cache data to the data cache simply by setting a couple of data source control properties. Programmatically Accessing Data using the Data Source Controls - programmatically retrieve, insert, delete, and update data using the SqlDataSource and AccessDataSource controls. Inserting Data - learn how to insert data using a SqlDataSource control. Also examines how to retrieve the `IDENTITY` column value for the just-inserted record. Deleting Data - see how to delete data using a SqlDataSource control. Also looks at how to programmatically cancel a delete. Updating Basics - learn the basics of updating database data using a SqlDataSource control. Also examines using the GridView to provide a web-based editing interface. (Subscribe to this Article Series! )

Data Source Control Basics - explores the concepts and advantages of data source controls, and compares their usage in ASP.NET 2.0 to data access techniques in ASP.NET 1.x.

Accessing Database Data - shows how to use the SqlDataSource and AccessDataSource controls to query data from a relational database.

Retrieving XML Data with XmlDataSource Control - see how to retrieve both remote and local XML data and display it in a data Web control.

Creating Custom Parameter Controls - learn how to create your own custom, declarative Parameter controls for use in the data source controls' parameters collections.

Examining the Data Source Control's Events - explore the events raised during a data source control's lifecycle.

Declaratively Caching Data - learn how to cache data to the data cache simply by setting a couple of data source control properties.

Programmatically Accessing Data using the Data Source Controls - programmatically retrieve, insert, delete, and update data using the SqlDataSource and AccessDataSource controls.

Inserting Data - learn how to insert data using a SqlDataSource control. Also examines how to retrieve the IDENTITY column value for the just-inserted record.

Deleting Data - see how to delete data using a SqlDataSource control. Also looks at how to programmatically cancel a delete.

Updating Basics - learn the basics of updating database data using a SqlDataSource control. Also examines using the GridView to provide a web-based editing interface.

(Subscribe to this Article Series! )

ASP.NET 2.0's data source controls make it possible to retrieve, insert, update, and delete data without having to write the tedious dedata access code that was so commonplace in ASP.NET version 1.x. Previous installments of this article series have looked at returning, inserting, and deleting data using the SqlDataSource control. However, we have yet to look at updating data.

In addition to the SqlDataSource control, ASP.NET 2.0 introduces three new data Web controls: the GridView, the DetailsView, and the FormView. These controls can work in unison with the data source controls to facilitate inserting, updating, and deleting data. In this article we will examine basics of using the SqlDataSource and GridView controls to update records from a database. In particular, we look at enabling editing support in the GridView. Future installments will explore more advanced updating scenarios, such as customizing the GridView's editing interface and programmatically setting the updated values. Read on to learn more!

Accessing and Updating Data in ASP.NET: Deleting Data

mitchell@4guysfromrolla.com (Scott Mitchell) — Wed, 20 Jun 2007 00:00:00 GMT

A Multipart Series on ASP.NET's Data Source Controls

A Multipart Series on ASP.NET's Data Source Controls
ASP.NET 2.0 introduced a number of new Web controls designed for accessing and modifying data. These controls allow page developers to declaratively access and modify data without writing any code to perform the data access. This article is one in a series of articles on ASP.NET's new data source controls. Data Source Control Basics - explores the concepts and advantages of data source controls, and compares their usage in ASP.NET 2.0 to data access techniques in ASP.NET 1.x. Accessing Database Data - shows how to use the SqlDataSource and AccessDataSource controls to query data from a relational database. Filtering Database Data with Parameters - learn how to retrieve just a subset of database data based on hard-coded values and values from the querystring, other Web controls on the page, session variables, and so on. Retrieving XML Data with XmlDataSource Control - see how to retrieve both remote and local XML data and display it in a data Web control. Creating Custom Parameter Controls - learn how to create your own custom, declarative `Parameter` controls for use in the data source controls' parameters collections. Examining the Data Source Control's Events - explore the events raised during a data source control's lifecycle. Declaratively Caching Data - learn how to cache data to the data cache simply by setting a couple of data source control properties. Programmatically Accessing Data using the Data Source Controls - programmatically retrieve, insert, delete, and update data using the SqlDataSource and AccessDataSource controls. Inserting Data - learn how to insert data using a SqlDataSource control. Also examines how to retrieve the `IDENTITY` column value for the just-inserted record. Deleting Data - see how to delete data using a SqlDataSource control. Also looks at how to programmatically cancel a delete. (Subscribe to this Article Series! )

Data Source Control Basics - explores the concepts and advantages of data source controls, and compares their usage in ASP.NET 2.0 to data access techniques in ASP.NET 1.x.

Accessing Database Data - shows how to use the SqlDataSource and AccessDataSource controls to query data from a relational database.

Retrieving XML Data with XmlDataSource Control - see how to retrieve both remote and local XML data and display it in a data Web control.

Creating Custom Parameter Controls - learn how to create your own custom, declarative Parameter controls for use in the data source controls' parameters collections.

Examining the Data Source Control's Events - explore the events raised during a data source control's lifecycle.

Declaratively Caching Data - learn how to cache data to the data cache simply by setting a couple of data source control properties.

Programmatically Accessing Data using the Data Source Controls - programmatically retrieve, insert, delete, and update data using the SqlDataSource and AccessDataSource controls.

Inserting Data - learn how to insert data using a SqlDataSource control. Also examines how to retrieve the IDENTITY column value for the just-inserted record.

Deleting Data - see how to delete data using a SqlDataSource control. Also looks at how to programmatically cancel a delete.

(Subscribe to this Article Series! )

ASP.NET 2.0's data source and data Web controls make working with data much easier than in previous versions by allowing for a declarative approach to working with data. In short, the data source controls make it possible to retrieve, insert, update, and delete data without having to write the tedious dedata access code that was so commonplace in ASP.NET version 1.x. (A previous installment of this article series examined using the SqlDataSource to insert data into a database.)

In this article we will focus on using the SqlDataSource control to delete records from a database. Specifically, we will look at three examples: using a SqlDataSource and a bit of server-side code to delete a record selected from a drop-down list; and using the GridView Web control's built-in deleting support; and how to programmatically cancel a delete operation. Read on to learn more!

Accessing and Updating Data in ASP.NET: Inserting Data

mitchell@4guysfromrolla.com (Scott Mitchell) — Tue, 01 May 2007 00:00:00 GMT

A Multipart Series on ASP.NET's Data Source Controls

A Multipart Series on ASP.NET's Data Source Controls
ASP.NET 2.0 introduced a number of new Web controls designed for accessing and modifying data. These controls allow page developers to declaratively access and modify data without writing any code to perform the data access. This article is one in a series of articles on ASP.NET's new data source controls. Data Source Control Basics - explores the concepts and advantages of data source controls, and compares their usage in ASP.NET 2.0 to data access techniques in ASP.NET 1.x. Accessing Database Data - shows how to use the SqlDataSource and AccessDataSource controls to query data from a relational database. Filtering Database Data with Parameters - learn how to retrieve just a subset of database data based on hard-coded values and values from the querystring, other Web controls on the page, session variables, and so on. Retrieving XML Data with XmlDataSource Control - see how to retrieve both remote and local XML data and display it in a data Web control. Creating Custom Parameter Controls - learn how to create your own custom, declarative `Parameter` controls for use in the data source controls' parameters collections. Examining the Data Source Control's Events - explore the events raised during a data source control's lifecycle. Declaratively Caching Data - learn how to cache data to the data cache simply by setting a couple of data source control properties. Programmatically Accessing Data using the Data Source Controls - programmatically retrieve, insert, delete, and update data using the SqlDataSource and AccessDataSource controls. Inserting Data - learn how to insert data using a SqlDataSource control. Also examines how to retrieve the `IDENTITY` column value for the just-inserted record. (Subscribe to this Article Series! )

Data Source Control Basics - explores the concepts and advantages of data source controls, and compares their usage in ASP.NET 2.0 to data access techniques in ASP.NET 1.x.

Accessing Database Data - shows how to use the SqlDataSource and AccessDataSource controls to query data from a relational database.

Retrieving XML Data with XmlDataSource Control - see how to retrieve both remote and local XML data and display it in a data Web control.

Creating Custom Parameter Controls - learn how to create your own custom, declarative Parameter controls for use in the data source controls' parameters collections.

Examining the Data Source Control's Events - explore the events raised during a data source control's lifecycle.

Declaratively Caching Data - learn how to cache data to the data cache simply by setting a couple of data source control properties.

Programmatically Accessing Data using the Data Source Controls - programmatically retrieve, insert, delete, and update data using the SqlDataSource and AccessDataSource controls.

Inserting Data - learn how to insert data using a SqlDataSource control. Also examines how to retrieve the IDENTITY column value for the just-inserted record.

(Subscribe to this Article Series! )

ASP.NET 2.0's data source and data Web controls make working with data much easier than in previous versions. These controls allow for a declarative approach to working with data, without needing to write any cumbersome data access code. The articles we have explored in the series thus far have focused on understanding the core concepts of the data source controls and how to retrieve data from the database. In addition to retrieving data, the data source controls can also insert, update, and delete data.

In this article we will focus on using the SqlDataSource control to insert records into a database. We will look at three examples: using a SqlDataSource and to insert a record using values entered by the user through various TextBoxes, DropDownLists, and other Web controls on an ASP.NET page; inserting using a SqlDataSource and a DetailsView control; and determining the value of the just-inserted record's IDENTITY column. Read on to learn more!

Accessing and Updating Data in ASP.NET: Programmatically Accessing Data using the Data Source Controls

mitchell@4guysfromrolla.com (Scott Mitchell) — Wed, 11 Apr 2007 00:00:00 GMT

A Multipart Series on ASP.NET's Data Source Controls

A Multipart Series on ASP.NET's Data Source Controls
ASP.NET 2.0 introduced a number of new Web controls designed for accessing and modifying data. These controls allow page developers to declaratively access and modify data without writing any code to perform the data access. This article is one in a series of articles on ASP.NET's new data source controls. Data Source Control Basics - explores the concepts and advantages of data source controls, and compares their usage in ASP.NET 2.0 to data access techniques in ASP.NET 1.x. Accessing Database Data - shows how to use the SqlDataSource and AccessDataSource controls to query data from a relational database. Filtering Database Data with Parameters - learn how to retrieve just a subset of database data based on hard-coded values and values from the querystring, other Web controls on the page, session variables, and so on. Retrieving XML Data with XmlDataSource Control - see how to retrieve both remote and local XML data and display it in a data Web control. Creating Custom Parameter Controls - learn how to create your own custom, declarative `Parameter` controls for use in the data source controls' parameters collections. Examining the Data Source Control's Events - explore the events raised during a data source control's lifecycle. Declaratively Caching Data - learn how to cache data to the data cache simply by setting a couple of data source control properties. Programmatically Accessing Data using the Data Source Controls - programmatically retrieve, insert, delete, and update data using the SqlDataSource and AccessDataSource controls. (Subscribe to this Article Series! )

Data Source Control Basics - explores the concepts and advantages of data source controls, and compares their usage in ASP.NET 2.0 to data access techniques in ASP.NET 1.x.

Accessing Database Data - shows how to use the SqlDataSource and AccessDataSource controls to query data from a relational database.

Retrieving XML Data with XmlDataSource Control - see how to retrieve both remote and local XML data and display it in a data Web control.

Creating Custom Parameter Controls - learn how to create your own custom, declarative Parameter controls for use in the data source controls' parameters collections.

Examining the Data Source Control's Events - explore the events raised during a data source control's lifecycle.

Declaratively Caching Data - learn how to cache data to the data cache simply by setting a couple of data source control properties.

Programmatically Accessing Data using the Data Source Controls - programmatically retrieve, insert, delete, and update data using the SqlDataSource and AccessDataSource controls.

(Subscribe to this Article Series! )

Working with data in ASP.NET version 1.x required writing data access code. This involved establishing a connection to the database, specifying the SQL command, and then executing the command. ASP.NET 2.0's data source controls greatly simplifies this process by encapsulating the data access pattern within a Web control construct. As such, data can be retrieved or modified and bound to a Web control without writing a single line of code. We explored the essentials of declarative data binding earlier in this article series in the Data Source Control Basics and Accessing Database Data articles.

In addition to being used declaratively, the data source Web controls can also be accessed programmatically. It is possible to add a SqlDataSource or AccessDataSource control to a web page, specify SELECT, INSERT, UPDATE, or DELETE queries, and then to programmatically execute one of the control's SQL commands. Such an approach is useful when you need to work with data programmatically, but want to avoid having to write the boilerplate data access code. In short, using the data source controls in this manner allows for data to be accessed programmatically with a single line of code.

In this article we will examine how to use the SqlDataSource control to programmatically retrieve, insert, and delete data. Read on to learn more!

Accessing and Updating Data in ASP.NET: Declaratively Caching Data

mitchell@4guysfromrolla.com (Scott Mitchell) — Wed, 24 Jan 2007 00:00:00 GMT

A Multipart Series on ASP.NET's Data Source Controls

A Multipart Series on ASP.NET's Data Source Controls
ASP.NET 2.0 introduced a number of new Web controls designed for accessing and modifying data. These controls allow page developers to declaratively access and modify data without writing any code to perform the data access. This article is one in a series of articles on ASP.NET's new data source controls. Data Source Control Basics - explores the concepts and advantages of data source controls, and compares their usage in ASP.NET 2.0 to data access techniques in ASP.NET 1.x. Accessing Database Data - shows how to use the SqlDataSource and AccessDataSource controls to query data from a relational database. Filtering Database Data with Parameters - learn how to retrieve just a subset of database data based on hard-coded values and values from the querystring, other Web controls on the page, session variables, and so on. Retrieving XML Data with XmlDataSource Control - see how to retrieve both remote and local XML data and display it in a data Web control. Creating Custom Parameter Controls - learn how to create your own custom, declarative `Parameter` controls for use in the data source controls' parameters collections. Examining the Data Source Control's Events - explore the events raised during a data source control's lifecycle. Declaratively Caching Data - learn how to cache data to the data cache simply by setting a couple of data source control properties. (Subscribe to this Article Series! )

Data Source Control Basics - explores the concepts and advantages of data source controls, and compares their usage in ASP.NET 2.0 to data access techniques in ASP.NET 1.x.

Accessing Database Data - shows how to use the SqlDataSource and AccessDataSource controls to query data from a relational database.

Retrieving XML Data with XmlDataSource Control - see how to retrieve both remote and local XML data and display it in a data Web control.

Creating Custom Parameter Controls - learn how to create your own custom, declarative Parameter controls for use in the data source controls' parameters collections.

Examining the Data Source Control's Events - explore the events raised during a data source control's lifecycle.

Declaratively Caching Data - learn how to cache data to the data cache simply by setting a couple of data source control properties.

(Subscribe to this Article Series! )

The ASP.NET 2.0 data source controls provide a declarative means for accessing and working with data. Simply set a few properties of the data source control, bind it to a data Web control, and, voila, data is being retrieved and displayed without having written a single line of code!

In addition to working with data declaratively, the data source controls can also cache data declaratively. Caching is a common technique used in data-driven applications to boost performance, and works by storing database data in memory where it can be more efficiently accessed. ASP.NET provides the data cache, which is a programmatically-accessible cache that is commonly used to store database results. See Caching in ASP.NET for more details on using the data cache and other caching options in ASP.NET.

What's worth noting about the data source controls is that they offer declarative access to the data cache. By simply setting a few properties, the data source controls will happily store their retrieved data in the data cache. Then, the next time the data source is asked to retrieve data, they'll pull that data from the cache instead of returning to the database. In this article we'll explore how to setup a data source control so that it stores it caches its results. Read on to learn more!

Accessing and Updating Data in ASP.NET: Examining the Data Source Control's Events

mitchell@4guysfromrolla.com (Scott Mitchell) — Wed, 22 Nov 2006 00:00:00 GMT

A Multipart Series on ASP.NET's Data Source Controls

A Multipart Series on ASP.NET's Data Source Controls
ASP.NET 2.0 introduced a number of new Web controls designed for accessing and modifying data. These controls allow page developers to declaratively access and modify data without writing any code to perform the data access. This article is one in a series of articles on ASP.NET's new data source controls. Data Source Control Basics - explores the concepts and advantages of data source controls, and compares their usage in ASP.NET 2.0 to data access techniques in ASP.NET 1.x. Accessing Database Data - shows how to use the SqlDataSource and AccessDataSource controls to query data from a relational database. Filtering Database Data with Parameters - learn how to retrieve just a subset of database data based on hard-coded values and values from the querystring, other Web controls on the page, session variables, and so on. Retrieving XML Data with XmlDataSource Control - see how to retrieve both remote and local XML data and display it in a data Web control. Creating Custom Parameter Controls - learn how to create your own custom, declarative `Parameter` controls for use in the data source controls' parameters collections. Examining the Data Source Control's Events - explore the events raised during a data source control's lifecycle. (Subscribe to this Article Series! )

Data Source Control Basics - explores the concepts and advantages of data source controls, and compares their usage in ASP.NET 2.0 to data access techniques in ASP.NET 1.x.

Accessing Database Data - shows how to use the SqlDataSource and AccessDataSource controls to query data from a relational database.

Retrieving XML Data with XmlDataSource Control - see how to retrieve both remote and local XML data and display it in a data Web control.

Creating Custom Parameter Controls - learn how to create your own custom, declarative Parameter controls for use in the data source controls' parameters collections.

Examining the Data Source Control's Events - explore the events raised during a data source control's lifecycle.

(Subscribe to this Article Series! )

The data source controls in ASP.NET 2.0 provide a simple, declarative approach for accessing and modifying data. The Data Source Control Basics article that kicked off this article series examined how to add data source controls to a page, specify the data to retrieve and/or modify, and bind that data to a data Web control (such as a GridView, DetailsView, or FormView). While point-and-click data access is useful for prototyping and for beginners or hobbyists who have little to no programming experience, wizards and the like are generally frowned upon by more seasoned developers since they typically offer ease of use at the cost of extensibility and customizability. The ASP.NET 2.0 data source controls, however, provide the best of both worlds, in my opinion - they can be quickly and easily configured to work with data, yet through a myriad of events that are raised during the data source controls' lifecycles, provide the flexibility for use in more advanced scenarios.

The SqlDataSource and ObjectDataSource controls are the two most commonly used data source controls, and they provide a means for retrieving and modifying data from either a database or object library, respectively. Both controls raise pre- and post-action events when selecting, inserting, updating, and deleting data. For example, the SqlDataSource and ObjectDataSource raise their Selecting events immediately before performing the SQL query or invoking the object method to retrieve data. After the data has been retrieved, the Selected events fires. By creating a Selecting event handler, you can examine and massage the parameters used in selecting data; the Selected event indicates, among other things, if an exception occurred during the operation. Similarly named pre- and post-action events fire during the updating, inserting, and deleting processes, as well.

Having a solid understanding of the data source events and event lifecycle has a slew of benefits. Many real-world scenarios require that the parameters being used for selecting, inserting, updating, or deleting be programmatically assigned or altered, which can be accomplished in the appropriate pre-action event. Moreover, to gracefully handle database- or object library-level exceptions in the page, the post-action event handlers should be used. And when debugging, the pre-action events provide an opportunity for examining what parameters (if any) are being used to query the data. Read on to learn more!

Accessing and Updating Data in ASP.NET: Creating Custom Parameter Controls

mitchell@4guysfromrolla.com (Scott Mitchell) — Wed, 01 Nov 2006 00:00:00 GMT

A Multipart Series on ASP.NET's Data Source Controls

A Multipart Series on ASP.NET's Data Source Controls
ASP.NET 2.0 introduced a number of new Web controls designed for accessing and modifying data. These controls allow page developers to declaratively access and modify data without writing any code to perform the data access. This article is one in a series of articles on ASP.NET's new data source controls. Data Source Control Basics - explores the concepts and advantages of data source controls, and compares their usage in ASP.NET 2.0 to data access techniques in ASP.NET 1.x. Accessing Database Data - shows how to use the SqlDataSource and AccessDataSource controls to query data from a relational database. Filtering Database Data with Parameters - learn how to retrieve just a subset of database data based on hard-coded values and values from the querystring, other Web controls on the page, session variables, and so on. Retrieving XML Data with XmlDataSource Control - see how to retrieve both remote and local XML data and display it in a data Web control. Creating Custom Parameter Controls - learn how to create your own custom, declarative `Parameter` controls for use in the data source controls' parameters collections. (Subscribe to this Article Series! )

Data Source Control Basics - explores the concepts and advantages of data source controls, and compares their usage in ASP.NET 2.0 to data access techniques in ASP.NET 1.x.

Accessing Database Data - shows how to use the SqlDataSource and AccessDataSource controls to query data from a relational database.

Retrieving XML Data with XmlDataSource Control - see how to retrieve both remote and local XML data and display it in a data Web control.

Creating Custom Parameter Controls - learn how to create your own custom, declarative Parameter controls for use in the data source controls' parameters collections.

(Subscribe to this Article Series! )

As discussed in previous installments of this article series, ASP.NET 2.0 ships with a number of built-in data source controls that can be used to programmatically access data (the SqlDataSource, ObjectDataSource, XmlDataSource, and so on). The SqlDataSource and ObjectDataSource commonly return or modify data based upon parameters. For example, a SqlDataSource might use a parameterized query, like SELECT * FROM TableName WHERE ColumName = @parameterName; the ObjectDataSource's parameters are those expected input parameters to the methods it invokes. In either case, the values of the parameters can be specified using Parameter controls. (See Filtering Database Data with Parameters installment for more information on using parameters with the data source controls.)

A Parameter controls is a control whose purpose is to provide a value for a given parameter. ASP.NET 2.0 ships with seven Parameter controls - the generic ControlParameter and the more specific ControlParameter, CookieParameter, FormParameter, ProfileParameter, QueryStringParameter, and SessionParameter controls - which pull their values from web controls on the page, session state, querystring fields, and so on.

If you need to use a value that's not provided by one of the specific Parameter controls, you can use the generic Parameter control and set its value programmatically (a topic we'll address in a future article in this series). Alternatively, you can create a custom Parameter control that grabs the specific data you need. Creating such a custom Parameter control is quite easy and straightforward, as we'll see in this article. Read on to learn more!

Accessing and Updating Data in ASP.NET: Retrieving XML Data with XmlDataSource Control

mitchell@4guysfromrolla.com (Scott Mitchell) — Wed, 27 Sep 2006 00:00:00 GMT

A Multipart Series on ASP.NET's Data Source Controls
ASP.NET 2.0 introduced a number of new Web controls designed for accessing and modifying data. These controls allow page developers to declaratively access and modify data without writing any code to perform the data access. This article is one in a series of articles on ASP.NET's new data source controls. Data Source Control Basics - explores the concepts and advantages of data source controls, and compares their usage in ASP.NET 2.0 to data access techniques in ASP.NET 1.x. Accessing Database Data - shows how to use the SqlDataSource and AccessDataSource controls to query data from a relational database. Filtering Database Data with Parameters - learn how to retrieve just a subset of database data based on hard-coded values and values from the querystring, other Web controls on the page, session variables, and so on. Retrieving XML Data with XmlDataSource Control - see how to retrieve both remote and local XML data and display it in a data Web control. (Subscribe to this Article Series! )

A Multipart Series on ASP.NET's Data Source Controls

Data Source Control Basics - explores the concepts and advantages of data source controls, and compares their usage in ASP.NET 2.0 to data access techniques in ASP.NET 1.x.

Accessing Database Data - shows how to use the SqlDataSource and AccessDataSource controls to query data from a relational database.

Retrieving XML Data with XmlDataSource Control - see how to retrieve both remote and local XML data and display it in a data Web control.

(Subscribe to this Article Series! )

With its new declarative data source controls and improved data Web controls, ASP.NET 2.0 has greatly simplified the process of working with data. In Part 2 of this article series, Accessing Database Data, we looked at how to use the SqlDataSource control to retrieve data from a relational database, which could then be bound to any data Web control (such as the GridView, DetailsView, FormView, DataList, Repeater, and so on). XML data can be accessed (and displayed) just as easily with the XmlDataSource control.

The XmlDataSource control makes accessing, filtering, and transforming XML data a simple, code-free process. Additionally, the XPath() and XPathSelect() databinding methods added to ASP.NET 2.0 make displaying particular XML values or binding entire XML nodesets just as easy. And the XML data accessed can be from a local file or automatically downloaded from a specified URL. In this article we will examine how to use the XmlDataSource control and the XPath() and XPathSelect() databinding methods, displaying the results in a variety of data Web controls. Read on to learn more!

Accessing and Updating Data in ASP.NET: Filtering Database Data with Parameters

mitchell@4guysfromrolla.com (Scott Mitchell) — Wed, 01 Mar 2006 00:00:00 GMT

A Multipart Series on ASP.NET's Data Source Controls
ASP.NET 2.0 introduced a number of new Web controls designed for accessing and modifying data. These controls allow page developers to declaratively access and modify data without writing any code to perform the data access. This article is one in a series of articles on ASP.NET's new data source controls. Data Source Control Basics - explores the concepts and advantages of data source controls, and compares their usage in ASP.NET 2.0 to data access techniques in ASP.NET 1.x. Accessing Database Data - shows how to use the SqlDataSource and AccessDataSource controls to query data from a relational database. Filtering Database Data with Parameters - learn how to retrieve just a subset of database data based on hard-coded values and values from the querystring, other Web controls on the page, session variables, and so on. (Subscribe to this Article Series! )

A Multipart Series on ASP.NET's Data Source Controls

Data Source Control Basics - explores the concepts and advantages of data source controls, and compares their usage in ASP.NET 2.0 to data access techniques in ASP.NET 1.x.

Accessing Database Data - shows how to use the SqlDataSource and AccessDataSource controls to query data from a relational database.

(Subscribe to this Article Series! )

In Part 2 of this article series we looked at how to access relational database data using the AccessDataSource and SqlDataSource controls. However, in Part 2 we only looked at how to retrieve all of the records from a table, view, stored procedure, or ad-hoc SQL query. Often, we only want to retrieve a subset of data based on various criteria. When searching for a book on Amazon.com, for example, the search page retrieves only the data from the database that matches the search terms you entered; when viewing the details for a particular book, only the particular book's information is queried from the database.

Results are filtered in a SQL statement using the WHERE clause, which contains a boolean expression. For each record in the table being queried, the WHERE expression is evaluated to determine whether or not to include that record in the resultset.¹ For example, a SQL query like: SELECT ProductID, ProductName FROM Products WHERE UnitPrice < 15.00 will return the ProductID and ProductName column values for all records in the Products table for which the statement UnitPrice < 15.00 evaluates to True. In English, it returns all products that cost strictly less than fifteen bucks.

The SqlDataSource and AccessDataSource controls can define the value by which the query is filtered by using parameters, and these parameters can retrieve their values from a variety of sources, including: the querystring, session variables, other Web controls on the page, and so on. Like the connection string and SELECT query, the filter parameters values for a data source control can be set declaratively, meaning you do not need to write a line of code. These parameter values can also be set programmatically, though, for cases where you might need to base the filter value on programmatic logic (such as the currently logged-in user's username).

In this article we will examine how to declaratively filter the results of a SQL query using parameters in a SqlDataSource. We'll see examples of how to use hard-coded filter values, and well as examples with filter values taken from the querystring and other Web controls on the page. Read on to learn more!

Accessing and Updating Data in ASP.NET: Accessing Database Data

mitchell@4guysfromrolla.com (Scott Mitchell) — Wed, 22 Feb 2006 00:00:00 GMT

A Multipart Series on ASP.NET 2.0's Data Source Controls
ASP.NET 2.0 introduced a number of new Web controls designed for accessing and modifying data. These controls allow page developers to declaratively access and modify data without writing any code to perform the data access. This article is one in a series of articles on ASP.NET 2.0's new data source controls. Data Source Control Basics - explores the concepts and advantages of data source controls, and compares their usage in ASP.NET 2.0 to data access techniques in ASP.NET 1.x. Accessing Database Data - shows how to use the SqlDataSource and AccessDataSource controls to query data from a relational database. (Subscribe to this Article Series! )

A Multipart Series on ASP.NET 2.0's Data Source Controls

Data Source Control Basics - explores the concepts and advantages of data source controls, and compares their usage in ASP.NET 2.0 to data access techniques in ASP.NET 1.x.

Accessing Database Data - shows how to use the SqlDataSource and AccessDataSource controls to query data from a relational database.

(Subscribe to this Article Series! )

One of the coolest new features of ASP.NET 2.0 is its new Data Source controls. The Data Source controls are a collection of Web controls designed to provide a declarative approach to accessing and modifying data. In short, with the Data Source controls you can work with data without having to write a lick of data access code. Compare this to ASP.NET 1.x, which required oft-repeated code to access data. For example, to display the contents of a database table in a web page with ASP.NET 1.x, you'd need to write code to:

Connect to the database,
Issue the command,
Retrieve the results, and
Work with the results / bind them to a data Web control (such as a DataGrid)

While only five to ten lines of code is needed to perform these four steps, and libraries like the Data Access Application Block help reduce the volume of code that you need to write, the fact remains that in order to access or modify data in an ASP.NET 1.x application you must write code.

With ASP.NET 2.0, data can be accessed entirely from declarative markup. In this article we'll be examining how to access data from databases with the SqlDataSource and AccessDataSource controls. With both of these controls you can specify the SELECT query to use and any parameters in the WHERE clause as properties of the Data Source controls. The code to connect to the database, issue the command, and retrieve the results is handled internally by the Data Source control. With the declarative, "code free" Data Source controls you can create a page that displays database data in under 15 seconds and without having to write a line of code. Read on to learn more!
Read More >

Accessing and Updating Data in ASP.NET: Data Source Control Basics

mitchell@4guysfromrolla.com (Scott Mitchell) — Wed, 11 Jan 2006 00:00:00 GMT

A Multipart Series on ASP.NET's Data Source Controls
This article is one in a series of articles on ASP.NET's data source controls. Data Source Control Basics - explores the concepts and advantages of data source controls, and compares their usage in ASP.NET 2.0 to data access techniques in ASP.NET 1.x.

When I started my career as a web developer, Microsoft's Active Server Pages version 2.0 had just burst onto the scenes. Back in my day, web developers were responsible for writing code to both access and display data. That is, we had to write code that queried the database and then had to write more code to squirt out the appropriate data surrounded by the applicable HTML elements. ASP.NET version 1.x simplified this process with the host of data Web controls (the DataGrid, DataList, Repeater, DropDownList, and so on). With just two lines of code these controls could emit their own, proper HTML elements when given an arbitrary data source. Today, with ASP.NET version 2.0 and its data source controls, developers can both access data and display it without writing a lick of code. You kids have it so easy these days!

In a nutshell, the ASP.NET 2.0 data source controls provide a declarative way to work with data. Rather than having to write code to connect to a database, issue a command, and retrieve the results as a DataReader or DataSet, with the data source controls these instructions can be specified through the standard Web control syntax. (Of course behind the scenes, the data source controls are still performing the programmatic steps we had to take in ASP.NET 1.x.) Once a data source control has been properly configured, it can be bound to any data Web control. When the page is visited, the data Web control will automatically invoke the associated data source control, retrieve its data, and display it as configured.

While the data source controls are easy to get started with, there are a number of subtleties and issues that can cause headaches. In this article series we'll examine the five built-in data source controls in detail. This first part, however, examines the concepts shared among all five data source controls and how ASP.NET 2.0's data Web controls work with their associated data source controls at runtime. Read on to learn more!