How to add Postback control inside RadAjaxPanel

.aspx code

<telerik:RadScriptManager ID="ScriptManager" runat="server" AsyncPostBackTimeout="36000">

</telerik:RadScriptManager>

<telerik:RadAjaxPanel ID="RadAjaxPanel1" runat="server"> 

<asp:Button ID="Button1" runat="server" Text="Button" />

</telerik:RadAjaxPanel >

To convert the "Button1" into a post back control add the below code in the page load event.

.cs code

protected void Page_Load(object sender, EventArgs e)

{

   ScriptManager.RegisterPostBackControl(mngBtnExcel); 

}