How to change the Master Page dynamically

Question

I want to assign one master page dynamically for a pure aspx file, Anybody can tell me, how to do this?

Answer 1

You can override OnPreInit in your default.aspx.cs and set the master page based on some value in your querystring. Something like this:

protected override void OnPreInit(EventArgs e)
    {
        base.OnPreInit(e);
        if (Request.QueryString["Master"] == "Simple")
            MasterPageFile = "~/Masterpages/Simple.Master";
    }

EDIT: the cause of your error message might be covered by this question.