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Full Screen Application: Windows CE and Pocket PC

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4.77/5 (16 votes)

Jun 7, 2007

CPOL

1 min read

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Making a full screen application for Windows CE and Pocket PC devices.

Screenshot - fullpocket.jpgScreenshot - fullCE.jpg

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