在 VB2010 windows 窗体的开头播放 .wav/.mp3 文件？

Question

现在已经做了大约一年的 VB2010，最近开始突破我可以将哪种媒体纳入我的表单的界限。 不过，我无法播放 .wav 或 .mp3 文件。 我试图按照微软和其他编码网站上的教程进行操作，但没有成功。 任何帮助将不胜感激。

Answer 1

要播放波形文件，您可以简单地使用：

        My.Computer.Audio.Play("c:\temp\temp.wav")

如果您想播放 mp3、wav、midi，您可以进行一些 WIN32 API 调用。这是我几年前创建的一个类，可以让你轻松玩它们。在你的项目中创建一个名为 AudioFile.vb 的类并将其粘贴进去。不过我已经好几年没看这段代码了，嘿嘿，它可能会被清理掉。

''' <summary>
''' This class is a wrapper for the Windows API calls to play wave, midi or mp3 files.
''' </summary>
''' <remarks>
''' </remarks>
Public Class AudioFile
'***********************************************************************************************************
'        Class:  PlayFile
'   Written By:  Blake Pell (bpell@indiana.edu)
' Initial Date:  03/31/2007
' Last Updated:  02/04/2009
'***********************************************************************************************************

' Windows API Declarations
Private Declare Function mciSendString Lib "winmm.dll" Alias "mciSendStringA" (ByVal lpstrCommand As String, ByVal lpstrReturnString As String, ByVal uReturnLength As Int32, ByVal hwndCallback As Int32) As Int32

''' <summary>
''' Constructor:  Location is the filename of the media to play.  Wave files and Mp3 files are the supported formats.
''' </summary>
''' <param name="Location"></param>
''' <remarks></remarks>
Public Sub New(ByVal location As String)
    Me.Filename = location
End Sub

''' <summary>
''' Plays the file that is specified as the filename.
''' </summary>
''' <remarks></remarks>
Public Sub Play()

    If _filename = "" Or Filename.Length <= 4 Then Exit Sub

    Select Case Right(Filename, 3).ToLower
        Case "mp3"
            mciSendString("open """ & _filename & """ type mpegvideo alias audiofile", Nothing, 0, IntPtr.Zero)

            Dim playCommand As String = "play audiofile from 0"

            If _wait = True Then playCommand += " wait"

            mciSendString(playCommand, Nothing, 0, IntPtr.Zero)
        Case "wav"
            mciSendString("open """ & _filename & """ type waveaudio alias audiofile", Nothing, 0, IntPtr.Zero)
            mciSendString("play audiofile from 0", Nothing, 0, IntPtr.Zero)
        Case "mid", "idi"
            mciSendString("stop midi", "", 0, 0)
            mciSendString("close midi", "", 0, 0)
            mciSendString("open sequencer!" & _filename & " alias midi", "", 0, 0)
            mciSendString("play midi", "", 0, 0)
        Case Else
            Throw New Exception("File type not supported.")
            Call Close()
    End Select

    IsPaused = False

End Sub

''' <summary>
''' Pause the current play back.
''' </summary>
''' <remarks></remarks>
Public Sub Pause()
    mciSendString("pause audiofile", Nothing, 0, IntPtr.Zero)
    IsPaused = True
End Sub

''' <summary>
''' Resume the current play back if it is currently paused.
''' </summary>
''' <remarks></remarks>
Public Sub [Resume]()
    mciSendString("resume audiofile", Nothing, 0, IntPtr.Zero)
    IsPaused = False
End Sub

''' <summary>
''' Stop the current file if it's playing.
''' </summary>
''' <remarks></remarks>
Public Sub [Stop]()
    mciSendString("stop audiofile", Nothing, 0, IntPtr.Zero)
End Sub

''' <summary>
''' Close the file.
''' </summary>
''' <remarks></remarks>
Public Sub Close()
    mciSendString("close audiofile", Nothing, 0, IntPtr.Zero)
End Sub

Private _wait As Boolean = False
''' <summary>
''' Halt the program until the .wav file is done playing.  Be careful, this will lock the entire program up until the
''' file is done playing.  It behaves as if the Windows Sleep API is called while the file is playing (and maybe it is, I don't
''' actually know, I'm just theorizing).  :P
''' </summary>
''' <value></value>
''' <returns></returns>
''' <remarks></remarks>
Public Property Wait() As Boolean
    Get
        Return _wait
    End Get
    Set(ByVal value As Boolean)
        _wait = value
    End Set
End Property

''' <summary>
''' Sets the audio file's time format via the mciSendString API.
''' </summary>
''' <value></value>
''' <returns></returns>
''' <remarks></remarks>
ReadOnly Property Milleseconds() As Integer
    Get
        Dim buf As String = Space(255)
        mciSendString("set audiofile time format milliseconds", Nothing, 0, IntPtr.Zero)
        mciSendString("status audiofile length", buf, 255, IntPtr.Zero)

        buf = Replace(buf, Chr(0), "") ' Get rid of the nulls, they muck things up

        If buf = "" Then
            Return 0
        Else
            Return CInt(buf)
        End If
    End Get
End Property

''' <summary>
''' Gets the status of the current playback file via the mciSendString API.
''' </summary>
''' <value></value>
''' <returns></returns>
''' <remarks></remarks>
ReadOnly Property Status() As String
    Get
        Dim buf As String = Space(255)
        mciSendString("status audiofile mode", buf, 255, IntPtr.Zero)
        buf = Replace(buf, Chr(0), "")  ' Get rid of the nulls, they muck things up
        Return buf
    End Get
End Property

''' <summary>
''' Gets the file size of the current audio file.
''' </summary>
''' <value></value>
''' <returns></returns>
''' <remarks></remarks>
ReadOnly Property FileSize() As Integer
    Get
        Try
            Return My.Computer.FileSystem.GetFileInfo(_filename).Length
        Catch ex As Exception
            Return 0
        End Try
    End Get
End Property

''' <summary>
''' Gets the channels of the file via the mciSendString API.
''' </summary>
''' <value></value>
''' <returns></returns>
''' <remarks></remarks>
ReadOnly Property Channels() As Integer
    Get
        Dim buf As String = Space(255)
        mciSendString("status audiofile channels", buf, 255, IntPtr.Zero)

        If IsNumeric(buf) = True Then
            Return CInt(buf)
        Else
            Return -1
        End If
    End Get
End Property

''' <summary>
''' Used for debugging purposes.
''' </summary>
''' <value></value>
''' <returns></returns>
''' <remarks></remarks>
ReadOnly Property Debug() As String
    Get
        Dim buf As String = Space(255)
        mciSendString("status audiofile channels", buf, 255, IntPtr.Zero)

        Return Str(buf)
    End Get
End Property

Private _isPaused As Boolean = False
''' <summary>
''' Whether or not the current playback is paused.
''' </summary>
''' <value></value>
''' <returns></returns>
''' <remarks></remarks>
Public Property IsPaused() As Boolean
    Get
        Return _isPaused
    End Get
    Set(ByVal value As Boolean)
        _isPaused = value
    End Set
End Property

Private _filename As String
''' <summary>
''' The current filename of the file that is to be played back.
''' </summary>
''' <value></value>
''' <returns></returns>
''' <remarks></remarks>
Public Property Filename() As String
    Get
        Return _filename
    End Get
    Set(ByVal value As String)

        If My.Computer.FileSystem.FileExists(value) = False Then
            Throw New System.IO.FileNotFoundException
            Exit Property
        End If

        _filename = value
    End Set
End Property

结束类

以下是上述类的一些示例用法：

    Dim audio As New AudioFile("C:\Temp\YourMP3File.mp3")
    audio.Play()