Fileupload inside UpdatePanel

I have a updatepanel in the master-page and fileupload control in the content page where it was not working despite my use of trigger

The I did the following trick

Step 1:

In the code file of the master page I did the following

public void RegisterPostbackTrigger(Control fullPostBack)

{

ScriptManager1.RegisterPostBackControl(fullPostBack);

}

Step 2:

In the HTML code of the content page I had following lines

Step 3:

Inside the page load event of content page I did the following

protected void Page_Load(object sender, EventArgs e)

{

try

{

((ASP.pages_admin_master_master)Page.Master).RegisterPostbackTrigger(btnUpload);

}

catch

{

}

}