What is the preferred way to bind a radcombobox in a radgrid? - asp.net

Question

I've seen a lot of questions close to this but haven't found my answer. Here's the key points of my example below:
RadGrid has a GridTemplateColumn
GridTemplateColumn has a RadComboBox in it's EditItemTemplate
RadComboBox is bound to an ObjectDataSource and had a RequiredFieldValidator
SelectedValue='<%#Bind("SomeValue")%>' seems to work but causes validation issues
Setting RadComboBox1.SelectedValue in ItemDataBound event seems to be working
Is binding with code in the ItemDataBound the best way to do this? What's interesting is that setting SelectedValue='<%#Bind("SomeValue")%>' on the aspx page has the SelectedValue already set by the time I get the ItemDataBound but for some reason, a RequiredFieldValidator fails in edit mode when doing this unless I set the value AGAIN in ItemDataBound. Below is a stripped down version of my code.
<telerik:RadGrid ID="rgTasks" runat="server" AllowAutomaticInserts="false" AllowAutomaticUpdates="false" AutoGenerateColumns="False">
<MasterTableView DataKeyNames="Id">
<CommandItemSettings ShowRefreshButton="False"></CommandItemSettings>
<Columns>
<telerik:GridEditCommandColumn ButtonType="ImageButton" UniqueName="EditCommandColumn"></telerik:GridEditCommandColumn>
<telerik:GridBoundColumn DataField="Id" ReadOnly="True" UniqueName="Id" DataType="System.Int32" Visible="false"></telerik:GridBoundColumn>
<telerik:GridTemplateColumn UniqueName="TaskTypeId" HeaderText="Task" DataField="TaskTypeId" DefaultInsertValue="">
<ItemTemplate>
<%# Eval("TaskType.Name")%>
</ItemTemplate>
<EditItemTemplate>
<telerik:RadComboBox ID="rcbTaskTypeId" runat="server" EmptyMessage="Select TaskType..."
DataSourceID="odsTaskTypes" DataValueField="Id" DataTextField="Name" SelectedValue='<%#Bind("TaskTypeId")%>'>
</telerik:RadComboBox>
<asp:RequiredFieldValidator ID="rfvTaskTypeId" runat="server" ControlToValidate="rcbTaskTypeId" ErrorMessage="Task Type is required" Display="Dynamic"></asp:RequiredFieldValidator>
</EditItemTemplate>
</telerik:GridTemplateColumn>
</Columns>
</MasterTableView>
</telerik:RadGrid>
<asp:ObjectDataSource ID="odsTaskTypes" runat="server" SelectMethod="GetTaskTypes" TypeName="CAPAModel.CAPARepo.DataRepo"></asp:ObjectDataSource>
Protected Sub rgTasks_ItemDataBound(sender As Object, e As GridItemEventArgs) Handles rgTasks.ItemDataBound
If ((TypeOf e.Item Is GridEditableItem) AndAlso e.Item.IsInEditMode) Then
If Not String.IsNullOrEmpty(DataBinder.Eval(e.Item.DataItem, "TaskTypeId").ToString) Then
Dim rcbTaskTypeId As RadComboBox = e.Item.FindControl("rcbTaskTypeId")
rcbTaskTypeId.SelectedValue = DataBinder.Eval(e.Item.DataItem, "TaskTypeId")
End If
End If
End Sub
I saw some relevant questions but am looking for an explanation of how I SHOULD be doing this and why. Thanks.

Answer 1

The error occured because you have set two different datafield as DataValueField and SelectedValue. I suppose you want to show another field as selected other than data in DataValueField and DataTextField. Please take a look into the following code snippet.
ASPX:
<telerik:GridTemplateColumn DataField="test" FilterControlAltText="Filter RegistryValue column" HeaderText="test" SortExpression="test" UniqueName="test">
<EditItemTemplate>
<telerik:RadComboBox ID="RadComboBox1" Runat="server" DataSourceID="odsTaskTypes" DataTextField="Name" DataValueField="Id" >
</telerik:RadComboBox>
</EditItemTemplate>
<ItemTemplate>
<asp:Label ID="RegistryValueLabel" runat="server" Text='<%# Eval("RegistryValue") %>'></asp:Label>
</ItemTemplate>
</telerik:GridTemplateColumn>
C#:
protected void gridiew1_ItemDataBound(object sender, GridItemEventArgs e)
{
if (e.Item is GridEditableItem && e.Item.IsInEditMode)
{
GridEditableItem editItem = (GridEditableItem)e.Item;
RadComboBox combo = (RadComboBox)editItem.FindControl("RadComboBox1");
combo.SelectedItem.Text = (string)DataBinder.Eval(e.Item.DataItem, "TaskTypeId").ToString();
}
}

Answer 2

So I've gone back and forth with Telerik support on this and their suggestion was to just do it the way I'm doing it. Considering that I'm binding the control in the code, I can probably get rid of SelectedValue='<%#Bind("TaskTypeId")%>' like so:
<telerik:RadComboBox ID="rcbTaskTypeId" runat="server"
DataSourceID="odsTaskTypes" DataValueField="Id" DataTextField="Name" >
</telerik:RadComboBox>
...and then just keep the code as is:
Protected Sub rgTasks_ItemDataBound(sender As Object, e As GridItemEventArgs) Handles rgTasks.ItemDataBound
If ((TypeOf e.Item Is GridEditableItem) AndAlso e.Item.IsInEditMode) Then
If Not String.IsNullOrEmpty(DataBinder.Eval(e.Item.DataItem, "TaskTypeId").ToString) Then
Dim rcbTaskTypeId As RadComboBox = e.Item.FindControl("rcbTaskTypeId")
rcbTaskTypeId.SelectedValue = DataBinder.Eval(e.Item.DataItem, "TaskTypeId")
End If
End If
End Sub