C# Determining if a form is completely off screen.

Question

I am developing an application that remembers the user's preferences as to where the form was last located on screen. In some instances the user will have it on a secondary screen, and then fire the app up later without the second screen (sometimes having the form appear off screen). Other times the user will change their resolution resulting in a similar effect.

I was hoping to do this checking in the Form_Shown event handler. Basically I want to determine wether the form is completly off screen so I can reposition it.

Any advice? Thanks!

Answer 1

Don't reposition your forms. Let the user handle that.

Answer 2

check with this function if Form is fully on screen:

public bool IsOnScreen(Form form)
     {
      Screen[] screens = Screen.AllScreens;
      foreach (Screen screen in screens)
      {
       Rectangle formRectangle = new Rectangle(form.Left,form.Top,form.Width, form.Height);

       if (screen.WorkingArea.Contains(formRectangle))
       {
        return true;
       }
      }

      return false;
     }

checking only TopLeft point if it's on screen:

public bool IsOnScreen(Form form)
     {
      Screen[] screens = Screen.AllScreens;
      foreach (Screen screen in screens)
      {
       Point formTopLeft = new Point(form.Left, form.Top);

       if (screen.WorkingArea.Contains(formTopLeft))
       {
        return true;
       }
      }

      return false;
     }

Answer 3

Check the screens resolution before you position the window. That will allow you to figure out if you where going to place it outside the bounds of the resolution, before you actually do it.