Question : How to find dynamic control in Silverlight 3.0?

Hello Experts,
 I'm using silverlight 3.0 and I created a text box at run time...But I couldn't find that textbox.... What will I do that?
 My C# code as follows
TextBox txtusername1 = new TextBox { Name = "txtusername", Height = 50, Width = 250, FontSize = 20, TextAlignment = TextAlignment.Center, TextWrapping = TextWrapping.Wrap, Foreground = new SolidColorBrush(Color.FromArgb(255, 173, 216, 230)), Opacity = 0.7 };
 txtusername1.SetValue(Canvas.TopProperty , -70d);
Button btnlogin= new Button { Height = 50, Width = 130, Content = "Login",Name="btnLogin" };
btnlogin.SetValue(Canvas.TopProperty, 70d);
btnlogin.Click += new RoutedEventHandler(btnlogin_Click);
void btnlogin_Click(object sender, RoutedEventArgs e)
{
loginwcfClient wcfclientobj = new loginwcfClient();
 wcfclientobj.getloginCompleted += newEventHandler(wcfclientobj_getloginCompleted);
wcfclientobj.getloginAsync(((TextBox)this.FindName("txtusername")).Text) //Error }
}
because txtusername returns null value How to get it? Thanks in Advance

Answer : How to find dynamic control in Silverlight 3.0?

Try to find you control using FindControl("controlId");
If you use this you should also set the ID property of the textbox to ID="controlId"