<script runat="server">
    protected void RadGrid1_NeedDataSource(object sender, Telerik.Web.UI.GridNeedDataSourceEventArgs e)
    {
        (sender as RadGrid).DataSource = Enumerable.Range(1, 10).Select(x => new { Id = x, Name = "Name " + x });
    }
</script>

<telerik:RadFormDecorator ID="RadFormDecorator1" runat="server" DecorationZoneID="test" DecoratedControls="All" />
<div id="test">
    <telerik:RadGrid ID="RadGrid1" runat="server" OnNeedDataSource="RadGrid1_NeedDataSource" AutoGenerateColumns="true"
        EnableHeaderContextMenu="true" FilterType="HeaderContext">
    </telerik:RadGrid>
</div>