Adding a Data-Dependent DropDownList to the DataGrid's Footer

This example shows adding a data-dependent DropDownList Web control to the footer of the DataGrid. The user can add a new FAQ by simply selecting the category and typing in the FAQ Question from the DropDownList and TextBox Web controls in the footer.

 FAQ IDCategoryFAQ Question
Edit 2 Strings How do you convert a string to all uppercase or all lowercase?
Edit 12 Email How can I display line breaks in an email message?
Edit 14 Email Can I send emails without using CDONTS?
Edit 15 Strings How can I determine the length of a string (how many characters are in a string)?
Edit 17 Strings How can I find the position of a certain character (or substring) within a string?
Edit 19 Dates and Times How can I return the current date/time?
Edit 20 Functions and Subroutines What is recursion?
Edit 23 FileSystemObject What, exactly, is the FileSystemObject?
Edit 25 Email How can I send an email using CDONTS?
Edit 8 Databases, General How do you create a database table through a SQL statement (via an ASP page, perhaps)?
Edit 16 Dates and Times Using VBScript, how can I determine if a variable is a valid date or not?
Edit 18 Dates and Times How can I easily display a nicely formatted date variable?
Edit 24 FileSystemObject How can I read the contents of a text file through an ASP page?
Edit 7 Arrays How do I dynamically resize an array?
Edit 11 Email How can I have my ASP page send HTML-formatted email?
Edit 10 Databases, General How can I tell what version of ADO I am using?
Edit 13 Email How do you send email attachments through an ASP page?
Edit 21 Arrays How can I determine the upper or lower bounds of an array?
Edit 22 Email How can I validate an email adress using Jscript?

Source Code
<% @Import Namespace="System.Data" %>
<% @Import Namespace="System.Data.SqlClient" %>
<script language="vb" runat="server">
  'Create a connection
  Dim myConnection as New SqlConnection(ConfigurationSettings.AppSettings("connectionString"))
  Dim ddlDataSet as DataSet = New DataSet()

  Sub Page_Load(sender as Object, e as EventArgs)
    If Not Page.IsPostBack then
    End If
  End Sub

  Sub BindData()
    '2. Create the command object, passing in the SQL string
    Const strSQL as String = "SELECT FAQID, F.FAQCategoryID, F.Description, FC.Name AS CategoryName FROM tblFAQ F INNER JOIN tblFAQCategory FC ON F.FAQCategoryID = FC.FAQCategoryID WHERE FAQID <= 25"

    'Set the datagrid's datasource to the datareader and databind
    Dim resultsDataSet as New DataSet()
    Dim myDataAdapter as SqlDataAdapter = New SqlDataAdapter(strSQL, myConnection) 

    dgPopularFAQs.DataSource = resultsDataSet
  End Sub

  Function GetCategories() as DataSet
    'Populate the ddlDataSet
    Const strSQLDDL as String = _
         "SELECT FAQCategoryID, Name FROM tblFAQCategory ORDER BY Name"    
    Dim myDataAdapter as SqlDataAdapter = New _
                          SqlDataAdapter(strSQLDDL, myConnection)    
    myDataAdapter.Fill(ddlDataSet, "Categories")

    Return ddlDataSet
  End Function

  Function GetSelectedIndex(CID as String) as Integer
    Dim iLoop as Integer
    Dim dt as DataTable = ddlDataSet.Tables("Categories")
    For iLoop = 0 to dt.Rows.Count - 1
      If Int32.Parse(CID) = Int32.Parse(dt.Rows(iLoop)("FAQCategoryID")) then
        Return iLoop
      End If
    Next iLoop
  End Function

  Sub dgPopFAQs_Edit(sender As Object, e As DataGridCommandEventArgs)
    dgPopularFAQs.EditItemIndex = e.Item.ItemIndex
    dgPopularFAQs.ShowFooter = False
  End Sub

  Sub dgPopFAQs_Cancel(sender As Object, e As DataGridCommandEventArgs)
    dgPopularFAQs.EditItemIndex = -1
    dgPopularFAQs.ShowFooter = True
  End Sub

  Sub dgPopFAQs_Update(sender As Object, e As DataGridCommandEventArgs)
    Response.Write("<b>The Update Command has no effect on this live demo...</b>")
    dgPopularFAQs.EditItemIndex = -1
  End Sub
  Sub dgPopFAQs_Insert(sender as Object, e As DataGridCommandEventArgs)
    If e.CommandName = "Insert" then
      Dim txtNewDescription as TextBox = e.Item.FindControl("txtNewDescription")
      Dim lstCategoriesInsert as DropDownList = e.Item.FindControl("lstCategoriesInsert")
      Response.Write("<b>The Insert Command has no effect on this live demo...</b><br />")
      Response.Write("<b>The data you would have inserted, though, was:<ul>")
      Response.Write("<li>" & lstCategoriesInsert.SelectedItem.Text & "</li>")
      Response.Write("<li>" & txtNewDescription.Text & "</li></ul></b>")
    End If
  End Sub

  <form runat="server">
    <asp:datagrid id="dgPopularFAQs" runat="server"

	    <asp:EditCommandColumn EditText="Edit" CancelText="Cancel" UpdateText="OK" />
	    <asp:TemplateColumn ItemStyle-Width="10%"
	        ItemStyle-HorizontalAlign="Center" HeaderText="FAQ ID"
	        <%# Container.DataItem("FAQID") %>	      
	        <asp:Button Text="Add" CommandName="Insert" runat="server" />
	    <asp:TemplateColumn HeaderText="Category">
            <%# DataBinder.Eval(Container.DataItem, "CategoryName") %>
	        <asp:DropDownList runat="server" id="lstCategories"
	              DataValueField="FAQCategoryID"  DataTextField="Name"
	              DataSource='<%# GetCategories() %>'
	              SelectedIndex='<%# GetSelectedIndex(Container.DataItem("FAQCategoryID")) %>' />
	        <asp:DropDownList runat="server" id="lstCategoriesInsert"
	              DataValueField="FAQCategoryID"  DataTextField="Name"
	              DataSource='<%# GetCategories() %>' />


	    <asp:TemplateColumn HeaderText="FAQ Question">
	        <%# Container.DataItem("Description") %>
	        <asp:TextBox runat="server" Text='<%# Container.DataItem("Description") %>' 
	               Columns="80" />
	        <asp:TextBox id="txtNewDescription" runat="server" Columns="80" />

[Return to the article]