accessing web controls from a master master page

[jrenae]

Hello,
I just started working with nested master pages....

I have a grandparent master page that has an <asp:Label id="lblUserName" runat=server>. In the code behind I can reference it just fine, but when I put a nested master page in between my grandparent master page and my content page, when the parent master page loads and tries to access his own control "lblUserName" I get an "Object reference not set to an instance of an object" error. If I have the content page reference the grandparent master page directly (no nested master) it works great, but as soon as I try to have my content page belong to a nested master page (which has the grandparent master as his master), the web control lblUserName is null.

This is the code in the GrandParentMaster code behind page.

    private String _userName;
    private User _thisUser;

    public String UserName
    {
        get
        {
            _userName = this.lblUserName.Text; //errs on this line
            return _userName;
        }
        set
        {
            _userName = value;
            this.lblUserName.Text = _userName; //or errs on this line


        }

    }

any advice would be appreciated.
Thanks much!