or

<telerik:GridDateTimeColumn DataField="Date" HeaderStyle-Width="135px" HeaderText="Date" ColumnEditorID="dateEditor" SortExpression="Date" UniqueName="Date" PickerType="DatePicker" > <ColumnValidationSettings EnableRequiredFieldValidation="True" > <RequiredFieldValidator ForeColor="Red" ErrorMessage="This field is required" ID="reqDateVal" ></RequiredFieldValidator> </ColumnValidationSettings> </telerik:GridDateTimeColumn>

<telerik:RadGrid ID="RadGrid1" runat="server" AutoGenerateColumns="False" AllowSorting="False" AllowMultiRowSelection="False" AllowPaging="False" OnNeedDataSource="RadGrid1_NeedDataSource" OnDetailTableDataBind="RadGrid1_DetailTableDataBind" Skin="Default"> <MasterTableView DataKeyNames="col1" ExpandCollapseColumn-ButtonType="PushButton"> <DetailTables> <telerik:GridTableView Name="detailGrid" Width="95%" BorderStyle="Solid" BorderWidth="1px" HorizontalAlign="Center"> <Columns> <telerik:GridBoundColumn HeaderText="col1" HeaderButtonType="TextButton" DataField="col1" /> <telerik:GridBoundColumn HeaderText="col2" HeaderButtonType="TextButton" DataField="col2" /> </Columns> </telerik:GridTableView> </DetailTables> <Columns>.....
