How to: Play Sounds

Artigo
06/18/2009

[This documentation is for preview only, and is subject to change in later releases. Blank topics are included as placeholders.]

This example demonstrates how to use platform invoke to play two WAV files, one as an embedded resource and the other as content.

To implement your WAV file as an embedded resource in Visual Studio, in the Properties pane, set its Build Action property to "Embedded Resource." If you are compiling at the command line, see How to: Compile at the Command Prompt for information about compiling an embedded resource.

Note

The .NET Compact Framework version 3.5 supports SoundPlayer to play sounds. For more information, see SoundPlayer in the .NET Compact Framework.

This example defines the Sound class that provides the following native code functionality by using CoreDll.dll in Windows CE:

Platform invoke method declarations to play a sound by using a file name or a stream.
An enumeration of bit values for passing arguments in the platform invoke method call.
A Play method that calls the correct platform invoke method to play a separate file or embedded resource.

This example uses a sound file named Chimes.wav compiled as an embedded resource. After you add the sound file to the project in Visual Studio, you must set its Build Action property to Embedded Resource in Solution Explorer. When you include the sound file as an embedded resource, you return the resource stream for the file by prepending the assembly namespace to the original file name in the call to GetManifestResourceStream.

Note

Alternatively, you can include the sound file as a project resource in Visual Studio and refer to the resource by name in your code. For more information, see Adding and Editing Resources (Visual C#) or How to: Retrieve Audio Resources in Visual Basic.

To play sounds using platform invoke

Add the Sound class to your projects.

Public Class Sound
   Private m_soundBytes() As Byte
    Private m_fileName As String

    Public Declare Function WCE_PlaySound Lib "CoreDll.dll" Alias "PlaySound" (ByVal szSound As String, ByVal hMod As IntPtr, ByVal flags As Integer) As Integer
    Public Declare Function WCE_PlaySoundBytes Lib "CoreDll.dll" Alias "PlaySound" (ByVal szSound() As Byte, ByVal hMod As IntPtr, ByVal flags As Integer) As Integer



   Private Enum Flags
      SND_SYNC = &H0 ' play synchronously (default) 
      SND_ASYNC = &H1 ' play asynchronously 
      SND_NODEFAULT = &H2 ' silence (!default) if sound not found 
      SND_MEMORY = &H4 ' pszSound points to a memory file 
      SND_LOOP = &H8 ' loop the sound until next sndPlaySound 
      SND_NOSTOP = &H10 ' don't stop any currently playing sound 
      SND_NOWAIT = &H2000 ' don't wait if the driver is busy 
      SND_ALIAS = &H10000 ' name is a registry alias 
      SND_ALIAS_ID = &H110000 ' alias is a predefined ID 
      SND_FILENAME = &H20000 ' name is file name 
      SND_RESOURCE = &H40004 ' name is resource name or atom 
    End Enum


    ' Construct the Sound object to play sound data from the specified file.
    Public Sub New(ByVal fileName As String)
        m_fileName = fileName
    End Sub


    ' Construct the Sound object to play sound data from the specified stream.
    Public Sub New(ByVal stream As Stream)
        ' read the data from the stream
        m_soundBytes = New Byte(stream.Length) {}
        stream.Read(m_soundBytes, 0, Fix(stream.Length))
    End Sub 'New


    ' Play the sound
    Public Sub Play()
        ' If a file name has been registered, call WCE_PlaySound, 
        ' otherwise call WCE_PlaySoundBytes.
        If Not (m_fileName Is Nothing) Then
            WCE_PlaySound(m_fileName, IntPtr.Zero, Fix(Flags.SND_ASYNC Or Flags.SND_FILENAME))
        Else
            WCE_PlaySoundBytes(m_soundBytes, IntPtr.Zero, Fix(Flags.SND_ASYNC Or Flags.SND_MEMORY))
        End If
    End Sub 
End Class

public class Sound
{
    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 Sound (string fileName) {
        m_fileName = fileName;
    }

    /// <summary>
    /// Construct the Sound object to play sound data from the specified stream.
    /// </summary>
    public Sound(Stream stream)    {
        // read the data from the stream
        m_soundBytes = new byte [stream.Length];
        stream.Read(m_soundBytes, 0,(int)stream.Length);
    }

    /// <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_ASYNC | Flags.SND_FILENAME));
        else
            WCE_PlaySoundBytes (m_soundBytes, IntPtr.Zero, (int) (Flags.SND_ASYNC | Flags.SND_MEMORY));
    }
}

Add methods to create an instance of the Sound class and to play a file, such as in a button's Click event.

' To return a Stream object associated with an embedded
' resource, you must prepend the namespace to the original
' name of the file in the project.
Private Sub btnEmbedded_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnEmbedded.Click
    Dim sound As New Sound([Assembly].GetExecutingAssembly().GetManifestResourceStream("SoundSample.chimes.wav"))
    sound.Play()
End Sub 


Private Sub btnFile_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnFile.Click
    Dim sound As New Sound("Program Files\SoundSample\chord.wav")
    sound.Play()
End Sub

// To return a Stream object associated with an embedded
// resource, you must prepend the namespace to the original
// name of the file in the project.
private void btnEmbedded_Click(object sender, System.EventArgs e) {
    Sound sound = new Sound (Assembly.GetExecutingAssembly().GetManifestResourceStream("SoundSample.chimes.wav"));
    sound.Play();
}

private void btnFile_Click(object sender, System.EventArgs e) {
    Sound sound = new Sound ("Program Files\\SoundSample\\chord.wav");
    sound.Play();
}

Compiling the Code

This example requires references to the following namespaces:

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How to: Play Sounds

To play sounds using platform invoke

Compiling the Code

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