Add html conetnt in header template

[Sreedhar]

<telerik:RadGrid ID="RadGrid1" runat="server" AutoGenerateColumns="false" AllowPaging="True"

                        OnNeedDataSource="RadGrid1_NeedDataSource" OnPreRender="RadGrid1_PreRender" OnItemCommand="RadGrid1_ItemCommand"

                        OnItemDataBound="RadGrid1_ItemDataBound" OnItemCreated="RadGrid1_ReportItemCreated">

                        <MasterTableView CommandItemDisplay="Top">

                            <Columns>

                                <telerik:GridTemplateColumn>

                                    <HeaderTemplate>

 

<tr class="subHeader" runat="server" id="headerTr">

<!-- I want to add html tags here from C# code behind -->

</tr>

                    </HeaderTemplate>

                                    <ItemTemplate>

Sample HTML that I want to add there is 
<th class="subHeader rgHeader">
                                                Test
                                            </th>
                                            <th class="subHeader rgHeader">
                                            </th>
                                            <th class="subHeader rgHeader">
                                                Test
                                            </th>

I also want to add HTML <ItemTemplate>


[Princy]

Hello Sreedhar,

You can try the same approach in the following help documentation.
Customizing with GridTemplateColumn.

Thanks,
Princy

[Sreedhar]

I don't want to fill entire grid with data I have customized the data in objects and I want to add other empty tags for expand collapse functionality. So, I wanted to customize templates