DotNetIdeas

Provisioning Windows Mobile Devices

noreply@blogger.com (DotNetIdeas) — Fri, 06 Nov 2009 21:09:00 +0000

Recently I worked on a project in which I need to create a configuration tool for windows mobile device, so it can setup the device ID, date/time, Network connection, Wi-Fi, etc. I used the windows mobile provisioning tool. There are more information on MSDN web site on how to use it. I am not going to repeat that. However, I want to document the issues I ran into while implementing it. Hope this will help others.

Note: The devices I was configuring are Intermec CN50 and Symbol MC75 with windows mobile 6 professional.

To use the provisioning tool, you will create a XML file with the following format. It contains the things you want to configure.

<wap-provisioningdoc>
    <characteristic type="Registry">
        <characteristic type="HKCU\ControlPanel\Owner">
            <parm name="Name" value="[DeviceID]"/>
            <parm name="Owner" value="[DeviceIDBinary]" datatype="binary"/>
        </characteristic>
    </characteristic>
</wap-provisioningdoc>

Then in your code you will load the XML into a XmlDocument variable and call ProcessConfiguration()

XmlDocument xd = new XmlDocument();
xd.LoadXml(XMLContent);
XmlDocument xdResult = ConfigurationManager.ProcessConfiguration(xd, false);

Setup Device ID

There is a DeviceInformation Configuration Service Provider, but surprisingly I couldn't find how you would setup the device ID. So I used Registry configuration service provider to update the registry.

<wap-provisioningdoc>
    <characteristic type="Registry">
        <characteristic type="HKCU\ControlPanel\Owner">
            <parm name="Name" value="[DeviceID]"/>
            <parm name="Owner" value="[DeviceIDBinary]" datatype="binary"/>
        </characteristic>
        <characteristic type="HKCU\Software\Microsoft\Bluetooth\Settings">
            <parm name="LocalName" value="[DeviceID]" datatype="string"/>
        </characteristic>
        <characteristic type="HKLM\Ident">
            <parm name="Name" value="[DeviceID]" datatype="string"/>
        </characteristic>
</wap-provisioningdoc>

Notice the [DeviceIDBinary] field? I didn't have that in there at first. But after changing the DeviceID, it didn't change the owner info displayed on the Today screen, even after a reboot. After researching the registry, I found out that I have to change the Owner field and that is a binary field.

Also most of the time, you will need to specify the datatype. Otherwise you may get an error code 2147500037, or something like that.

Set VPN connection

Using CM_VPNEntries Configuration Service Provider to set VPN connection is very straight forward. Here is the sample XML. If you have more than one, you can set Enabled to 1 to make it default.

<characteristic type="CM_VPNEntries">
    <characteristic type="MyVPN">
        <parm name="SrcId" value="{436EF144-B4FB-4863-A041-8F905A62C572}"/>
        <parm name="DestId" value="{A1182988-0D73-439e-87AD-2A5B369F808B}"/>
        <parm name="Phone" value="[MyIP]"/>
        <parm name="UserName" value="[UserName]"/>
        <parm name="Password" value="[Password]"/>
        <parm name="Domain" value="[MyDomain]"/>
        <!--Determins the type of authentication e.g. IPSec = 1 vs PPTP = 0-->
        <parm name="Type" value="0"/>
        <!--Determins the type IPSec encryption, either pre shared key or cert based-->
        <parm name="IPSecAuth"  value="1"/>
        <!--pre shared key can be 256 chars long, but must be ASCII-->
        <parm name="PresharedKey" value="[NetworkKey]"/>
        <parm name="Enabled" value="0" />
    </characteristic>
</characteristic>

Wi-Fi configuration

The XML to configure Wi-Fi is simple, just follow Wi-Fi Configuration Service Provider. However, there are a couple of things worth mention. First, we need to turn on Wi-Fi before apply the XML file, otherwise it will throw a error code. Second, this only worked for Intermec device. The Symbol device has its own way configuring Wi-Fi. I have to export their setting and use Registry configuration service provider to configure it.

<characteristic type="Wi-Fi">
    <characteristic type="access-point">
        <characteristic type="[MyAccessPointName]">
            <parm name="DestId" value="{436EF144-B4FB-4863-A041-8F905A62C572}"/>
            <parm name="Encryption" value="0"/>
            <parm name="Authentication" value="0"/>
            <parm name="Hidden" value="0"/>
            <parm name="KeyProvided" value="0"/>
            <parm name="NetworkKey" value="[NetworkKey]"/>
            <parm name="KeyIndex" value="1"/>
            <parm name="Use8021x" value="0"/>
        </characteristic>
    </characteristic>
</characteristic>

Add URL Exceptions

To add URL Exceptions in the screen showed here, use the following XML.

<characteristic type="CM_Mappings">
    <characteristic type="16842751">
        <parm name="Pattern" value="http://*/*" />
        <parm name="Network" value="{A1182988-0D73-439E-87AD-2A5B369F808B}" />
    </characteristic>
</characteristic>

GPRS configuration

I used CM_GPRSEntries Configuration Service Provider to configure GPRS. Nothing is special there.

<characteristic type="CM_GPRSEntries">
    <characteristic type="GPRS Connection">
        <parm name="DestId" value="{436EF144-B4FB-4863-A041-8F905A62C572}" />
        <parm name="UserName" value="[DeviceID]" />
        <parm name="Password" value="[Password]" />
        <parm name="Domain" value="[Domain]" />
        <parm name="AlwaysOn" value="1" />
        <characteristic type="DevSpecificCellular">
            <parm name="GPRSInfoValid" value="1" />
            <parm name="GPRSInfoAccessPointName" value="[AcceessPointName]" />
            <parm name="BearerInfoValid" value="1" />
            <parm name="GPRSInfoProtocolType" value="2" />
            <parm name="GPRSInfoL2ProtocolType" value="2" />
            <parm name="GPRSInfoAddress" value="" />
            <parm name="GPRSInfoDataCompression" value="1" />
            <parm name="GPRSInfoHeaderCompression" value="1" />
        </characteristic>
    </characteristic>
</characteristic>

Set Date/Time and Time Zone

In this application, we also need to set the date/time and time zone information. I tried to use the Clock Configuration Service Provider, but it doesn't work. I don't know what is wrong. I followed the sample xml, but I couldn't get it to work. Finally, since we only use 4 of the time zones, I queried the TimeZoneInformation for each time zone and exported the values. Then put those values in the application's configuration file. I load them in when the user choose a time zone and pass it to the following xml to set the time zone. To set the date/time, I used OpenNETCF.WinAPI.Core.SetLocalDateTime(). This is not pretty, but it worked.

<wap-provisioningdoc>
    <characteristic type="Registry">
        <characteristic type="HKLM\Time">
            <parm name="TimeZoneInformation" value="[TimeZoneInformation]" datatype="binary"/>
        </characteristic>
        <characteristic type="HKLM\Software\Microsoft\Clock">
            <parm name="GMT_OFFSET" value="[GMT_OFFSET]" datatype="integer"/>
        </characteristic>
    </characteristic>
</wap-provisioningdoc>

If you are changing the time zone and you need to display current date/time on your configuration screen like we did, you need to get the local time using native function call instead of using DateTime.Now. Otherwise, it will mess up.

Creating Transparent Controls in .NET Compact Framework

noreply@blogger.com (DotNetIdeas) — Wed, 07 Oct 2009 21:34:00 +0000

Recently I was working on improving the user interface of our windows mobile application - UnitConverter. It had plain solid background. I wanted to add background image to it. I found this video tutorial on how to display background image on a form. However, that tutorial told us if we need to have transparent controls on top of the image, we have to write our own user controls. That’s how I started researching on how to create transparent controls. I found an article by Per Ola Sæther which laid the foundation of my solution.

The basic ideas to create a transparent control is to override the OnPaintBackgound method of the control so it calls the parent form’s OnPaintBackgound to draw the background and then draw content of the control on top of it.

In that article, the author showed how to create a transparent label control. But the code can be simplified. I also did some refactoring work so it extends to not just label control.

First I created the same interface introduced in that article.

public interface IPaintControl
{
    // have the background painted
    void InvokePaintBackground(PaintEventArgs e);
}

Then I created a base form so I don’t have to write the same code for each form.

public class CcForm : Form, IPaintControl
{
    public virtual void InvokePaintBackground(PaintEventArgs e)
    {
        OnPaintBackground(e);
    }
}

A base control is created so we not only can have transparent label, but also other kinds of controls, such as radio button and checkbox. It has a property called “TransparentBackground”. If you don’t want your control to be transparent for some reason, you can change this property. In the “OnPaintBackground” method, it calls its parent’s “InvokePaintBackground” to draw the background.

public class CcTransparentControl : Control
{
    private bool _transparentBackgound = true;
    public bool TransparentBackground
    {
        get
        {
            return _transparentBackgound;
        }
        set
        {
            _transparentBackgound = value;
        }
    }

    protected override void OnPaintBackground(PaintEventArgs e)
    {
        if (_transparentBackgound)
        {
            IPaintControl parent = (IPaintControl)Parent;
            if (parent != null)
            {
                parent.InvokePaintBackground(e);
            }
        }
        else base.OnPaintBackground(e);
    }
}

Now we can create the transparent label control using the following code.

public class CcTransparentLabel : CcTransparentControl
{
    private ContentAlignment textAlign = ContentAlignment.TopLeft;
    public ContentAlignment TextAlign
    {
        get
        {
            return textAlign;
        }
        set
        {
            textAlign = value;
        }
    }

    public CcTransparentLabel()
    {

    }

    protected override void OnPaint(PaintEventArgs e)
    {
        Graphics gfx = e.Graphics;
        if (this.TextAlign == ContentAlignment.TopLeft)
        {
            gfx.DrawString(this.Text, this.Font,
            new SolidBrush(this.ForeColor), ClientRectangle);
        }
        else if (this.TextAlign == ContentAlignment.TopCenter)
        {
            SizeF size = gfx.MeasureString(this.Text, this.Font);
            int left = this.Width / 2 - (int)size.Width / 2;
            var rect = new Rectangle(ClientRectangle.Left + left,
            ClientRectangle.Top, (int)size.Width,
            ClientRectangle.Height);
            gfx.DrawString(this.Text, this.Font,
            new SolidBrush(this.ForeColor), rect);
        }
        else if (this.TextAlign == ContentAlignment.TopRight)
        {
            SizeF size = gfx.MeasureString(this.Text, this.Font);
            int left = this.Width - (int)size.Width + this.Left;
            var rect = new Rectangle(ClientRectangle.Left + left,
            ClientRectangle.Top, (int)size.Width,
            ClientRectangle.Height);
            gfx.DrawString(this.Text, this.Font,
            new SolidBrush(this.ForeColor), rect);
        }
    }

}

In our form, we change the form to inherit from CcForm and drag/drop a CcTransparentLabel onto it.

public partial class FormWithSolidColorBackground : CcForm

Here is the screen shot. As you can see, the label has transparent background now.

However, when I tried to add image background with gradient color, my label doesn’t look right anymore.

To understand the issue, we need to first take a look of how we display background image on a form.

public partial class FormWithImageBackground : CcForm
{
    private Rectangle _backgroundRect;
    private Bitmap _background;
    private string currentPath = Path.GetDirectoryName(Assembly.GetExecutingAssembly().GetName().CodeBase.ToString());

    public FormWithImageBackground()
    {
        InitializeComponent();

        _background = new Bitmap(currentPath + @"\ImageBackground.jpg");
        _backgroundRect = new Rectangle(0, 0, _background.Width, _background.Height);
    }

    protected override void OnPaintBackground(PaintEventArgs e)
    {
        Graphics g = e.Graphics;
        g.DrawImage(_background, this.ClientRectangle, _backgroundRect, GraphicsUnit.Pixel);
    }
}

What happened is when the OnPaintBackground was called by the transparent label control, it re-draws the image inside of the label control. So it shows the top-left corner of the image on the label’s background. To fix this issue, I pass in the location of the label control to the form and use it to re-draw the image. For example, if the label is located at (10, 20), the image background would be displayed at (-10, –20). This may not be the best solution, but it worked. Here is revised interface and controls.

public interface IPaintControl
{
    // have the background painted
    void InvokePaintBackground(PaintEventArgs e, Point location);
}

public class CcForm : Form, IPaintControl
{
    public virtual void InvokePaintBackground(PaintEventArgs e, Point location)
    {
        OnPaintBackground(e);
    }
}

public class CcTransparentControl : Control
{
    ....
    protected override void OnPaintBackground(PaintEventArgs e)
    {
        if (_transparentBackgound)
        {
            IPaintControl parent = (IPaintControl)Parent;
            if (parent != null)
            {
                parent.InvokePaintBackground(e, this.Location);
            }
        }
        else base.OnPaintBackground(e);
    }
}

In the form, I then override the InvokePaintBackground method to draw the image at the desired location.

public override void InvokePaintBackground(System.Windows.Forms.PaintEventArgs e, System.Drawing.Point location)
{
    Graphics g = e.Graphics;
    Rectangle destRect = new Rectangle(-1 * location.X, -1 * location.Y, ClientRectangle.Width, ClientRectangle.Height);
    g.DrawImage(_background, destRect, _backgroundRect, GraphicsUnit.Pixel);
}

Now we have a transparent label over image background.

I also created transparent radio button and checkbox controls. These are the controls commonly used in a form. So is the Panel control. The following example showed the transparent radio button and checkbox on a transparent panel. You can download the complete source code from here.

Memory leak issue in “How Do I: Programmatically Monitor for a Specific Time of Day Without Draining a Device Battery?”

noreply@blogger.com (DotNetIdeas) — Thu, 10 Sep 2009 20:15:00 +0000

Recently I worked on improving our SmartOrganizer 3.1 application. I need to add notification to it, so when a task or appointment is due, the application will prompt the user. Also I want this to run efficiently so it won’t drain the device battery. I found some sample code from “How Do I” video for Device.

Though the code worked well initially, I found a couple issues which caused memory leak later. Here I will post the original code and my fix.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Diagnostics;
using HowDoI.Examples;
using System.Threading;

namespace TimeOfDayEvent_CS
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        const string _eventName = @"TimeOfDayEventExample";
        const string _timeOfDayEventName = @"\\.\Notifications\NamedEvents\" + _eventName;
        IntPtr _nativeWaitHandle = IntPtr.Zero;
        Thread _backgroundThread = null;
        bool _programIsShuttingDown = false;
        private void menuSetTimeNtfy_Click(object sender, EventArgs e)
        {
            // Declare and convert time values
            DateTime targetTime = GetTargetTime();
            long targetTimeAsFileTimeUTC = targetTime.ToFileTime();
            long targetTimeAsFileTimeLocal = 0;
            Win32.FileTimeToLocalFileTime(ref targetTimeAsFileTimeUTC, 
                ref targetTimeAsFileTimeLocal);
            SystemTime targetTimeAsSystemTime = new SystemTime();
            Win32.FileTimeToSystemTime(ref targetTimeAsFileTimeLocal, targetTimeAsSystemTime);

            // Create named Win32 Event Object
            _nativeWaitHandle = Win32.CreateEvent(0, 0, 0, _eventName);

            // Start the background thread
            _backgroundThread = new Thread(ThreadFunction);
            _backgroundThread.Start();

            Win32.CeRunAppAtTime(_timeOfDayEventName, targetTimeAsSystemTime);
        }

        void ThreadFunction()
        {
            // Wait for the event to signal
            // When signaled our target time has happened
            Win32.WaitForSingleObject(_nativeWaitHandle, -1);

            // Do our Target Time processing
            if (!_programIsShuttingDown)
                BeginInvoke((TimeHasOccurredDelegate)TimeHasOccurred, new object[] { DateTime.Now }); 
            //TimeHasOccurred(DateTime.Now);
        }

        void TimeHasOccurred(DateTime time)
        {
            notification1.Text = 
                string.Format("<html><body><font color=\'#000000\'><b>It's Time: {0}<b></font></body></html>", 
                time.ToString());
            notification1.Visible = true;
            Debug.WriteLine("It's Time: " + time.ToString());
        }

        delegate void TimeHasOccurredDelegate(DateTime time);

        private DateTime GetTargetTime()
        {
            //DateTime targetTime = new DateTime(2007, 8, 31, 10, 15, 0);
            // For demo purposes pick date time 1 minute in the future
            DateTime currentTime = DateTime.Now;
            DateTime targetTime = currentTime + new TimeSpan(0, 1, 0);

            Debug.WriteLine("CurrentTime: " + currentTime.ToString());
            Debug.WriteLine("TargetTime: " + targetTime.ToString());

            return targetTime;
        }

        const int _threadShutdownTimeout = 30000;
        private void Form1_Closing(object sender, CancelEventArgs e)
        {
            if (_nativeWaitHandle != IntPtr.Zero)
            {
                _programIsShuttingDown = true;
                Win32.SetEvent(_nativeWaitHandle);
                if (_backgroundThread != null)
                {
                    bool shutdownSucceeded = _backgroundThread.Join(_threadShutdownTimeout);
                    if (!shutdownSucceeded)
                        _backgroundThread.Abort();
                }
            }
        }
    }
}

Here is the native method calls

using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;

namespace HowDoI.Examples
{
    static class Win32
    {
        #region Win32 Time-related Functiions

        [DllImport("CoreDLL.dll")]
        public static extern int CeRunAppAtTime(string application, SystemTime startTime);
        [DllImport("CoreDLL.dll")]
        public static extern int FileTimeToSystemTime(ref long lpFileTime, SystemTime lpSystemTime);
        [DllImport("CoreDLL.dll")]
        public static extern int FileTimeToLocalFileTime(ref long lpFileTime, ref long lpLocalFileTime);
        [DllImport("CoreDLL.dll")]
        public static extern int ShowWindow(IntPtr hWnd, int nCmdShow);

        #endregion

        #region Win32  Event Object Functions

        [DllImport("CoreDLL.dll")]
        public static extern IntPtr CreateEvent(int alwaysZero, int manualReset, int initialState, string eventName);
        [DllImport("CoreDLL.dll")]
        public static extern int WaitForSingleObject(IntPtr handle, int waitTimeInMilliseconds);
        [DllImport("CoreDLL.dll")]
        private static extern int EventModify(IntPtr handle, int eventAction);
        [DllImport("CoreDLL.dll")]
        public static extern int CloseHandle(IntPtr handle);

        public static int SetEvent(IntPtr handle)
        {
            const int EVENT_SET = 3;
            return EventModify(handle, EVENT_SET); // in WM, SetEvent, ResetEvent, & PulseEvent are all implemented as EventModify
        }
        
#endregion

    }

    #region Win32 SystemTime

    [StructLayout(LayoutKind.Sequential)]
    public class SystemTime
    {
        public ushort wYear;
        public ushort wMonth;
        public ushort wDayOfWeek;
        public ushort wDay;
        public ushort wHour;
        public ushort wMinute;
        public ushort wSecond;
        public ushort wMilliseconds;
    }

    #endregion

}

The time monitoring and notification in above code worked perfectly. However, I noticed that if I stop the application before the time is up, the application disappeared from the task manager, but the memory was not released. Furthermore, I used the Remote Process Viewer to check which process is running. I can see that process is still there. As I was writing this blog, I noticed that it only happen on device, not emulator. For some reasons, the device couldn’t kill the background thread when it is not done. The solution is. in fact, pretty simple - reset the timer. Add the following line of code before Join the background thread. [currentTime] is current time in SystemTime format.

Win32.CeRunAppAtTime(_timeOfDayEventName, [currentTime]);
bool shutdownSucceeded = _backgroundThread.Join(_threadShutdownTimeout);

This application requires a newer version of the Microsoft .NET Compact Framework than the version installed on this device

noreply@blogger.com (DotNetIdeas) — Tue, 25 Aug 2009 17:47:00 +0000

This is the second time I ran into this error in last couple months. I better write it down so I don’t forget again.

I was creating a .NET Compact Framework Application. I want it to be able to run on older devices, so I choose .NET Framework 2.0 thinking the project will be .NET 2.0 project(see picture 1). However, when I tried to run the application on a smart phone, I got the error “This application requires a newer version of the Microsoft .NET Compact Framework than the version installed on this device.” You have to specify the version of .NET Compact Framework on the second dialog box(see picture 2).

Picture 1

Picture 2

.NET Compact Framework Programming Tips

noreply@blogger.com (DotNetIdeas) — Thu, 14 May 2009 22:00:00 +0000

How to get entry assembly path?

/// <summary>
/// Simulate Assembly.GetEntryAssembly that is not supported by the Compact Framework.
/// </summary>
/// <returns>Path and name of first executable as a string.</returns>
public static string GetEntryAssembly()
{
    StringBuilder sb = null;
    IntPtr moduleHandler = GetCurrentModuleHandle();
    if (IntPtr.Zero != moduleHandler)
    {
        sb = new StringBuilder(255);
        if (0 == SafeGetModuleFileName(moduleHandler, sb, sb.Capacity))
        {
            sb = null;
        }
    }
    return sb.ToString();
}

/// <summary>
/// Safe wrapper for PINVOKE GetModuleHandle.
/// </summary>
/// <returns>A handle to the current module indicates success.</returns>
private static IntPtr GetCurrentModuleHandle()
{
    IntPtr moduleName = IntPtr.Zero;
    return GetModuleHandle(moduleName);
}

/// <summary>
/// Safe wrapper for PINVOKE GetModuleFileName.
/// </summary>
/// <param name="moduleHandler">Handle to the module whose executable file name is being requested.</param>
/// <param name="moduleName">Pointer to a buffer that is filled in with the path and file name of the given module. </param>
/// <param name="capacity"> Specifies the length, in characters, of the ModuleName buffer.</param>
/// <returns>The length, in characters, of the string copied to the buffer indicates success. </returns>
private static Int32 SafeGetModuleFileName(IntPtr moduleHandler, StringBuilder moduleName, Int32 capacity)
{
    if (capacity > 255)
    {
        capacity = 255;
    }
    return GetModuleFileName(moduleHandler, moduleName, capacity);
}

/// <summary>
/// PINVOKE that gets a module handle for the specified module if the file has been mapped into the address space of the calling process. 
/// </summary>
/// <param name="moduleName">Pointer to a null-terminated string that contains the name of the module, which must be a DLL file.</param>
/// <returns>A handle to the specified module indicates success.</returns>
[System.Runtime.InteropServices.DllImport("CoreDll.dll", SetLastError = true)]
public static extern IntPtr GetModuleHandle(IntPtr moduleName);

/// <summary>
/// PINVOKE that gets a module file name.
/// </summary>
/// <param name="moduleHandler">Handle to the module whose executable file name is being requested.</param>
/// <param name="moduleName">Pointer to a buffer that is filled in with the path and file name of the given module. </param>
/// <param name="capacity"> Specifies the length, in characters, of the ModuleName buffer.</param>
/// <returns>The length, in characters, of the string copied to the buffer indicates success. </returns>
[System.Runtime.InteropServices.DllImport("CoreDll.dll", SetLastError = true)]
public static extern Int32 GetModuleFileName(IntPtr moduleHandler, StringBuilder moduleName, Int32 capacity);

How to set a form foreground?

public static void SetForegroundWindow(Form form)
{
    form.Capture = true;
    IntPtr hwnd = GetCapture();
    form.Capture = false;
    SetForegroundWindow(hwnd);
}

[System.Runtime.InteropServices.DllImport("coredll.dll", SetLastError = true)]
public static extern bool SetForegroundWindow(IntPtr hWnd);

[System.Runtime.InteropServices.DllImport("coredll.dll", SetLastError = true)]
public static extern IntPtr GetCapture();

How to get memory status?

/// <summary>
/// Retrieves the memory status of the device
/// </summary>
public static MemoryStatus GlobalMemoryStatus()
{
    MemoryStatus ms = new MemoryStatus();
    GlobalMemoryStatusCE(out ms);
    return ms;
}

[System.Runtime.InteropServices.DllImport("coredll", EntryPoint = "GlobalMemoryStatus", SetLastError = false)]
public static extern void GlobalMemoryStatusCE(out MemoryStatus msce);

Below is the MemoryStatus structure used above

/// <summary>
/// Memory Status Structure
/// </summary>
public struct MemoryStatus
{
    /// <summary>
    /// Length of Structure
    /// </summary>
    internal int Length;
    /// <summary>
    /// Specifies a number between 0 and 100 that gives a general idea of current memory utilization, in which 0 indicates no memory use and 100 indicates full memory use.
    /// </summary>
    public int MemoryLoad;
    /// <summary>
    /// Indicates the total number of bytes of physical memory.
    /// </summary>
    public int TotalPhysical;
    /// <summary>
    /// Indicates the number of bytes of physical memory available.
    /// </summary>
    public int AvailablePhysical;
    /// <summary>
    /// Indicates the total number of bytes that can be stored in the paging file. Note that this number does not represent the actual physical size of the paging file on disk.
    /// </summary>
    public int TotalPageFile;
    /// <summary>
    /// Indicates the number of bytes available in the paging file.
    /// </summary>
    public int AvailablePageFile;
    /// <summary>
    /// Indicates the total number of bytes that can be described in the user mode portion of the virtual address space of the calling process.
    /// </summary>
    public int TotalVirtual;
    /// <summary>
    /// Indicates the number of bytes of unreserved and uncommitted memory in the user mode portion of the virtual address space of the calling process.
    /// </summary>
    public int AvailableVirtual;
}

How to prevent device fall asleep?

/// <summary>
/// This function resets a system timer that controls whether or not the
/// device will automatically go into a suspended state.
/// </summary>
[DllImport("CoreDll.dll")]
public static extern void SystemIdleTimerReset();

How to play sound in windows mobile?

noreply@blogger.com (DotNetIdeas) — Tue, 24 Feb 2009 21:19:00 +0000

Recently I created a Smart Device application called SightReader. There is a virtual piano keyboard in it and I need to play sound when the user clicks a key on keyboard. I was trying to use the WavPlayer I created before. It is easy to use, but it only support WAV file. I generated the sound MIDI file for each key and then converted them to WAV file. However I couldn’t get the wav file to be reasonable size. So the compiled executable was huge and impossible to use on a Smart Device. Finally I created another SoundPlayer which can play MIDI, MP3 and WAV file. It works fine except it has slower response time.

New update(3/3/2009): I really don't like the sound of the MIDI in my SightReader. So I searched and searched. Finally somebody mentioned that you can use "Sound Recorder" in Windows to reduce the size of a WAV file. But when I looked the Sound Recorder in Vista, I don't see any choice other than recording sound. So I went to a Windows 2000. Aha! Here we go. Now I was able to use audio format "11.025 khz, 16 Bit, Mono" to convert my once 200 KB WAV file to 22 KB. Other good things about the Sound Record is you can do some editing to the WAV file, such as increase the volume or deletion. It is a shame that Microsoft doesn't provide the same features in Vista.

How to play WAV file?

public class WavPlayer
{
    private byte[] m_soundBytes;
    private string m_fileName;
 
    private enum Flags
    {
        SND_SYNC = 0x0000,  /* play synchronously (default) */
        SND_ASYNC = 0x0001,  /* play asynchronously */
        SND_NODEFAULT = 0x0002,  /* silence (!default) if sound not found */
        SND_MEMORY = 0x0004,  /* pszSound points to a memory file */
        SND_LOOP = 0x0008,  /* loop the sound until next sndPlaySound */
        SND_NOSTOP = 0x0010,  /* don't stop any currently playing sound */
        SND_NOWAIT = 0x00002000, /* don't wait if the driver is busy */
        SND_ALIAS = 0x00010000, /* name is a registry alias */
        SND_ALIAS_ID = 0x00110000, /* alias is a predefined ID */
        SND_FILENAME = 0x00020000, /* name is file name */
        SND_RESOURCE = 0x00040004  /* name is resource name or atom */
    }

    [DllImport("CoreDll.DLL", EntryPoint = "PlaySound", SetLastError = true)]
    private extern static int WCE_PlaySound(string szSound, IntPtr hMod, int flags);
 
    [DllImport("CoreDll.DLL", EntryPoint = "PlaySound", SetLastError = true)]
    private extern static int WCE_PlaySoundBytes(byte[] szSound, IntPtr hMod, int flags);
 
    /// <summary>
    /// Construct the Sound object to play sound data from the specified file.
    /// </summary>
    public WavPlayer(string fileName)
    {
        m_fileName = fileName;
    }
 
    /// <summary>
    /// Construct the Sound object to play sound data from the specified stream.
    /// </summary>
    public WavPlayer(Stream stream)
    {
        // read the data from the stream
        m_soundBytes = new byte[stream.Length];
        stream.Read(m_soundBytes, 0, (int)stream.Length);
    }
 
    public WavPlayer(byte[] soundBytes)
    {
        m_soundBytes = soundBytes;
    }
 
 
    /// <summary>
    /// Play the sound
    /// </summary>
    public void Play()
    {
        // if a file name has been registered, call WCE_PlaySound,
        //  otherwise call WCE_PlaySoundBytes
        if (m_fileName != null)
            WCE_PlaySound(m_fileName, IntPtr.Zero, (int)(Flags.SND_SYNC | Flags.SND_FILENAME));
        else
            WCE_PlaySoundBytes(m_soundBytes, IntPtr.Zero, (int)(Flags.SND_SYNC | Flags.SND_MEMORY));
    }
}

How to play MIDI, MP3 and other sound?

This method will only work in Windows Mobile 6 and later.

public enum SoundFileType { WAV, MP3, MIDI, WMA }

public class SoundPlayer : IDisposable
{
    [DllImport("aygshell.dll")]
    static extern uint SndOpen(string pszSoundFile, ref IntPtr phSound);
 
    [DllImport("aygshell.dll")]
    static extern uint SndPlayAsync(IntPtr hSound, uint dwFlags);
 
    [DllImport("aygshell.dll")]
    static extern uint SndClose(IntPtr hSound);
 
    [DllImport("aygshell.dll")]
    static extern uint SndStop(int SoundScope, IntPtr hSound);
 
    [DllImport("aygshell.dll")]
    static extern uint SndPlaySync(string pszSoundFile, uint dwFlags);
 
    const int SND_SCOPE_PROCESS = 0x1;
    IntPtr sound = IntPtr.Zero;
    Thread soundThread = null;
 
    string _filePath = string.Empty;
    public string FilePath
    {
        get { return _filePath; }
        set { _filePath = value; }
    }
 
    public SoundPlayer(string filePath)
    {
        _filePath = filePath;
    }
 
    public SoundPlayer(byte[] soundBytes, SoundFileType fileType)
    {
        string fileExtension = ".wav";
        switch (fileType)
        {
            case SoundFileType.WAV:
                fileExtension = ".wav";
                break;
            case SoundFileType.MP3:
                fileExtension = ".mp3";
                break;
            case SoundFileType.MIDI:
                fileExtension = ".mid";
                break;
            default:
                throw new Exception("Audio format is not supported.");
                break;
        }
 
        _filePath = Path.GetTempPath() + "tempSound" + fileExtension;
        FileStream fs = new FileStream(_filePath, FileMode.Create, FileAccess.ReadWrite);
        fs.Write(soundBytes, 0, soundBytes.Length);
        fs.Close();
    }
 
    public void Play()
    {
        SndPlaySync(_filePath, 0);
    }
 
    public void PlayLooping()
    {
        soundThread = new Thread(Playing);
        soundThread.Start();
    }
 
    private void Playing()
    {
        while (true)
        {
            SndPlaySync(_filePath, 0);
        }
    }
 
    public void PlayAsync()
    {
        SndOpen(_filePath, ref sound);
        SndPlayAsync(sound, 0);
    }
 
    public void Stop()
    {
        if (soundThread != null)
        {
            SndStop(SND_SCOPE_PROCESS, IntPtr.Zero);
            soundThread.Abort();
            soundThread = null;
        }
        if (sound != IntPtr.Zero)
        {
            SndStop(SND_SCOPE_PROCESS, IntPtr.Zero);
            SndClose(sound);
            sound = IntPtr.Zero;
        }
    }
 
    #region IDisposable Members
 
    public void Dispose()
    {
        Stop();
    }
 
    #endregion
}

region