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I’d like to point out that this took me a while to figure out and in the end it was DisturbedBuddha over at the ASP.Net forums that gave me the solution. I thought I would share this with you as I know I would never have been able to imagine how to makes this work on my own.

I used a sample program and constructed it in 2 ways. First I created it the “normal” way by placing all the controls in the .ASPX file. Second I created the same program all in the CodeBehind. I needed to do this becuase I planned to wrap some AJAX functionality into a Composite Control.

I will attach the project at the bottom of this post.

The simple program contained a Label that read “init” on first load, a button that ran a javascript function to postback an event argument that would trigger the Label to be updated to “callback” and display a nice Ajaxy loading animation.

Was able to get everything to work great except I couldn’t get the UdateProgress’s ProgressTemplate created. Below I will post the VB and C# code of how to do this.

The code

VB

Partial Class Default9
    Inherits System.Web.UI.Page

    Protected Sub Page_PreRender(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.PreRender
        ' !!!THIS MUST BE DONE IN THE PRERENDER EVENT!!!
        ' Create the label.
        Dim lab As New Label
        lab.ID = "Label1"
        lab.Text = "Please wait..."

        ' Create the UpdateProgress.
        Dim uprog As New UpdateProgress
        uprog.AssociatedUpdatePanelID = UpdatePanel1.ClientID
        uprog.ID = "UpdateProgress1"

        ' Create the ProgressTemplate based on a class the implements ITemplate.
        Dim value As New MyTemplate
        uprog.ProgressTemplate = value

        ' Add the Label to the UpdateProgress and the UpdateProgress to the form.
        uprog.Controls.Add(lab)
        Form.Controls.Add(uprog)
    End Sub

End Class

' THIS GOES IN YOUR PAGES CODE BEHIND ALSO!
Public Class MyTemplate : Implements ITemplate

    Public Sub InstantiateIn(ByVal container As Control) Implements Web.UI.ITemplate.InstantiateIn
        ' This is empty.
    End Sub

End Class

C#

partial class Default9 : System.Web.UI.Page
{
	protected void Page_PreRender(object sender, System.EventArgs e)
	{
	 // !!!THIS MUST BE DONE IN THE PRERENDER EVENT!!!
	 // Create the label.
	 Label lab = new Label();
	 lab.ID = "Label1";
	 lab.Text = "Please wait...";

	 // Create the UpdateProgress.
	 UpdateProgress uprog = new UpdateProgress();
	 uprog.AssociatedUpdatePanelID = UpdatePanel1.ClientID;
	 uprog.ID = "UpdateProgress1";

	 // Create the ProgressTemplate based on a class the implements ITemplate.
	 MyTemplate value = new MyTemplate();
	 uprog.ProgressTemplate = value;

	 // Add the Label to the UpdateProgress and the UpdateProgress to the form.
	 uprog.Controls.Add(lab);
	 Form.Controls.Add(uprog);
	}
}

// THIS GOES IN YOUR PAGES CODE BEHIND ALSO!
public class MyTemplate : ITemplate
{
	public void InstantiateIn(Control container)
	{
	 // This is empty.
	}
}

I hope this helps someone else out. DisturbedBuddha says he is planning to post on his blog explaining the ins and outs of why this appraoch is necessary.

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This project was created using Visual Studio 2008 with the .Net Framework 2.0.

Get project source