Associate different Master Pages dynamically with a content page : Master page « Development « ASP.NET Tutorial

1. ASP.NET Tutorial
2. Development
3. Master page

File: Default.aspx

<%@ Page Language="C#" MasterPageFile="~/Default.master" %>
<script runat="server">

    protected void Page_PreInit(object sender, EventArgs e)
    {
        if (Request["master"] != null)
        {
            switch (Request["master"])
            {
                case "Dynamic1":
                    this.MasterPageFile = "Default.master";
                    break;
                case "Dynamic2":
                    this.MasterPageFile = "MasterDefault.master";
                    break;
            }
        }

        
    }
</script>

<asp:Content
    ID="Content1"
    ContentPlaceHolderID="ContentPlaceHolder1"
    Runat="Server">

    Select a Master Page:
    <ul class="selectMaster">
        <li>
        <a href="Default.aspx?master=Default">Dynamic Master 1</a>
        </li>
        <li>
        <a href="Default.aspx?master=MasterDefault">Dynamic Master 2</a>
        </li>
    </ul>

</asp:Content>