I once made a solution that runs on full screen. The solution was written completely in managed code (except for the CE Setup and other small stuff..). Since I took over the screen completely, I don't have access to the (X) button in the upper right corner of the screen. I wanted the application running at all times, but I also wanted the user to be able to get in and out of the application. Since the user won't be able to access the Start button, I added a "Close" button to my application. This "Close" button won't exit the application, instead it will just Minimize the application.

In the .NET Compact Framework 2.0, you can't just set the form's WindowState to WindowState.Minimized since the WindowState enum only contains Normal and Maximized. Currently, the only way you can programmatically minimize an application is by doing a P/Invoke to ShowWindow and passing SW_MINIMIZE to specify how the window will be displayed. It is also required that your Form has the Taskbar visible, this is done by setting the following properties:

  FormBorderStyle = FormBorderStyle.FixedDialog;
  WindowState = FormWindowState.Normal;
  ControlBox = true;
  MinimizeBox = true;
  MaximizeBox = true;

Here's a small code snippet of how to minimize your application

[DllImport("coredll.dll")]
static extern int ShowWindow(IntPtr hWnd, int nCmdShow);

const int SW_MINIMIZED = 6;

void Minimize() {
  // The Taskbar must be enabled to be able to do a Smart Minimize
  this.FormBorderStyle = FormBorderStyle.FixedDialog;
  this.WindowState = FormWindowState.Normal;
  this.ControlBox = true;
  this.MinimizeBox = true;
  this.MaximizeBox = true;

  // Since there is no WindowState.Minimize, we have to P/Invoke ShowWindow
  ShowWindow(this.Handle, SW_MINIMIZED);
}