RadGrid for ASP.NET AJAX

The built-in GridDropDownColumn is filtered by its ListValueField when the default filtering feature of the control is used. RadGrid does not include any support for filtering by ListTextField instead.

This limitation is because the filtering mechanism relies on the DataField of the filtered column and for GridDropDownColumn this property specifies the mapping field in the drop-down source. (For more information about the properties of GridDropDownColumn, see Customize/Configure GridDropDownColumn).If you want to filter by ListTextField, your current options are:

• use a hidden GridBoundColumn (with Display = false). Add an ItemCommand event handler that catches filter commands from GridBoundColumn and substitutes a filter command from the GridDropDownColumn instead:

  • ASPNET
  • C#
  • VB.NET

  CopyASPX

  <telerik:GridDropDownColumn UniqueName="CategoryddColumn" ListTextField="CategoryName"
    HeaderText="Category name" ListValueField="CategoryID" DataField="CategoryID" DataSourceID="dataSourceCategories">
  </telerik:GridDropDownColumn>
  <telerik:GridBoundColumn DataField="CategoryName" HeaderText="CategoryName" SortExpression="CategoryName"
    UniqueName="CategoryName" Display="false">
  </telerik:GridBoundColumn>

  CopyC#

  protected void RadGrid1_ItemCommand(object source, GridCommandEventArgs e)
  {
      if (e.CommandName == RadGrid.FilterCommandName)
      {
          Pair command = (Pair)e.CommandArgument;
          if (command.Second.ToString() == "CategoryddColumn")
          {
              e.Canceled = true;
              GridFilteringItem filter = (GridFilteringItem)e.Item;
              ((filter["CategoryName"].Controls[0]) as TextBox).Text = ((filter["CategoryddColumn"].Controls[0]) as TextBox).Text;
              command.Second = "CategoryName";
              filter.FireCommandEvent("Filter", new Pair(command.First, "CategoryName"));
          }
      }
  }
  protected void RadGrid1_ItemDataBound(object sender, GridItemEventArgs e)
  {  
      if (e.Item is GridFilteringItem) 
      {  
          GridFilteringItem item = e.Item as GridFilteringItem; 
          ((item["CategoryddColumn"].Controls[0]) as TextBox).Text = ((item["CategoryName"].Controls[0]) as TextBox).Text; 
      }
  }

  CopyVB.NET

  Protected Sub RadGrid1_ItemCommand(ByVal source As Object, ByVal e As GridCommandEventArgs) Handles RadGrid1.ItemCommand
      If e.CommandName = RadGrid.FilterCommandName Then
          Dim command As Pair = CType(e.CommandArgument, Pair)
          If command.Second.ToString = "CategoryddColumn" Then
              e.Canceled = True
              Dim filter As GridFilteringItem = CType(e.Item, GridFilteringItem)
   CType(filter("CategoryName").Controls(0), TextBox).Text = CType(filter("CategoryddColumn").Controls(0)), TextBox).Text   
              command.Second = "CategoryName"
              filter.FireCommandEvent("Filter", New Pair(command.First, "CategoryName"))
          End If
      End If
  End Sub
  Protected Sub RadGrid1_ItemDataBound(ByVal sender As Object, ByVal e As GridItemEventArgs) Handles RadGrid1.ItemDataBound
      If TypeOf e.Item Is GridFilteringItem Then
          Dim item As GridFilteringItem = TryCast(e.Item, GridFilteringItem)
          TryCast(item("CategoryddColumn").Controls(0), TextBox).Text = TryCast(item("CategoryName").Controls(0), TextBox).Text
      End If
  End Sub

• Use GridTemplateColumn instead of GridDropDownColumn. You can add a DropDownList in its EditItemTemplate to simulate the GridDropDownColumn.