problem to access textbox in login view

[diana04]

i dragged a loginview and then a text box in the logged templete but when i wrote a code behind this textbox ..it doesn't work and an error message "System.NullReferenceException: Object reference not set to an instance of an object." appeared.

Code on TextBox:
TextBox RequestDate = ((TextBox)LoginView1.FindControl("RequestDatetb")) ;
RequestDate.Text=System.DateTime.Today.ToShortDate String();

can any one help me to solve this problem..



Diana