Full Screen Application: Windows CE and Pocket PC

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• Download source - 21.7 KB

Introduction

Many developers must include a "full screen" feature into their applications. In this article, I am focusing on Pocket PC and Windows CE devices. I've tried to introduce a universal solution for PDA software developers using the .NET Compact Framework that will enable them to include a full screen mode on both platforms, without requiring recompilation or code changes.

Background

Why do we need a full screen mode on our PDAs? My three main reasons are:

• To disable user interaction and access other programs on the device
• To make full use of the screen space
• To customize forms

Using the code

There are three steps to my full screen solution.

1. Detecting the platform type by invoking Windows API and changing the form behavior accordingly:

   Platform type detection is a simple call to SystemParametersInfo to find whether you are running on a Smartphone or a Pocket PC. You need a few constants defined and the P/Invoke marshaling code to make it work from managed code. I am using SystemParametersInfo4Strings P/Invoke to detect if the device is a Pocket PC or not.

   public enum SystemParametersInfoActions : uint
   {
       SPI_GETPLATFORMTYPE = 257, 
       // this is used elsewhere for Smartphone/PocketPC detection
   
   }
   #endregion
   
   /// 
   
   /// Get Platform Type: Pocket Pc or Windows CE
   
   /// 
   
   /// 
   
   public static string GetPlatformType()
   {
       StringBuilder platformType = new StringBuilder(50);
       if (SystemParametersInfo4Strings(
       (uint)SystemParametersInfoActions.SPI_GETPLATFORMTYPE,
           (uint)platformType.Capacity, platformType, 0) == 0)
           throw new Exception("Error getting platform type.");
       return platformType.ToString();
   }

   Platform detection method:

   /// 
   
   /// Platform Detections methods
   
   /// 
   
   internal partial class PlatformDetection
   {
       public static bool IsSmartphone()
       {
           return PInvoke.GetPlatformType() == "SmartPhone";
       }
       public static bool IsPocketPC()
       {
           return PInvoke.GetPlatformType() == "PocketPC";
       }
   }

   P/Invoke descriptions:

   //to find whether you are running on a Smartphone or a Pocket PC
   
   [DllImport("Coredll.dll", EntryPoint = "SystemParametersInfoW", 
       CharSet = CharSet.Unicode)]
   tatic extern int SystemParametersInfo4Strings(uint uiAction, 
       uint uiParam, StringBuilder pvParam, uint fWinIni);
       
   //The GetCapture function retrieves a handle to the window  
   
   [DllImport("coredll.dll")]
   private static extern IntPtr GetCapture();
   
   //The SetCapture function sets the mouse capture to
   
   //the specified window belonging to the current thread   
   
   [DllImport("coredll.dll")]
   private static extern IntPtr SetCapture(IntPtr hWnd);
   
   //This function can be used to take over certain areas of the screen
   
   //It is used to modify the taskbar, Input Panel button,
   
   //or Start menu icon.
   
   [DllImport("aygshell.dll", SetLastError = true)]
   private static extern bool SHFullScreen(IntPtr hwnd, int state);
   
   //The function retrieves the handle to the top-level 
   
   //window whose class name and window name match 
   
   //the specified strings. This function does not search child windows.
   
   [DllImport("coredll.dll", SetLastError = true)]
   private static extern IntPtr FindWindowW(string lpClass, string
       lpWindow);
       
   //changes the position and dimensions of the specified window
   
   [DllImport("coredll.dll", SetLastError = true)]
   private static extern IntPtr MoveWindow(IntPtr hwnd, int x, 
       int y, int w, int l, int repaint);

   This code is of the "set full screen" method:

   //if not Pocket PC platform
   
   if (!Platform.PlatformDetection.IsPocketPC()) 
   {
       //Set Full Screen For Windows CE Device
   
   
       //Normalize windows state
   
       form.WindowState = FormWindowState.Normal;
   
       IntPtr iptr = form.Handle;
       SHFullScreen(iptr, (int)FullScreenFlags.HideStartIcon);
               
       //detect taskbar height
   
       int taskbarHeight = 
           Screen.PrimaryScreen.Bounds.Height - 
           Screen.PrimaryScreen.WorkingArea.Height;
   
       // move the viewing window north taskbar 
   
       // height to get rid of the command bar 
   
       MoveWindow(iptr, 0, -taskbarHeight, 
           Screen.PrimaryScreen.Bounds.Width, 
           Screen.PrimaryScreen.Bounds.Height + taskbarHeight, 1);
   
   
       // move the task bar south taskbar height so that it's 
   
       // not visible anylonger 
   
       IntPtr iptrTB = FindWindowW("HHTaskBar", null);
       MoveWindow(iptrTB, 0, Screen.PrimaryScreen.Bounds.Height, 
           Screen.PrimaryScreen.Bounds.Width, taskbarHeight, 1);
   }
   else //pocket pc platform
   
   {
       //Set Full Screen For Pocket Pc Device
   
       form.Menu = null;
       form.ControlBox = false;
       form.FormBorderStyle = FormBorderStyle.None;
       form.WindowState = FormWindowState.Maximized;
       form.Text = string.Empty;
   }

2. Calling the form load event's "make full screen" method:

   private void MainForm_Load(object sender, EventArgs e)
   {
       FullScreen.StartFullScreen(this);
   }

3. Calling the form closing event's "remove full screen" method:

   private void MainForm_Closing(object sender, CancelEventArgs e)
   {
       FullScreen.StopFullScreen(this);
   }

What is next?

In addition, you can customize forms as well as set your own title with battery life and your own close button. Let's do it!

History

• 7 June, 2007 -- Original article posted
• 13 June, 2007 -- Updated
• 14 June, 2007 -- Updated some more