Question

我阅读了一些关于如何使用mciSendString（）函数在VB.Net中播放WAV文件的教程。由于某种原因，它成功地录制并将声音保存到文件中（我用声音应用程序收听了文件），但没有播放任何内容并且没有触发错误。

以下是代码：

'Start recording
If OvalShape1.FillColor = Color.DarkRed Then
    OvalShape1.FillColor = Color.Red

    Try
        mciSendString("open new Type waveaudio Alias recsound", "", 0, 0)
        mciSendString("record recsound", "", 0, 0)
    Catch ex As Exception
        MessageBox.Show(ex.ToString)
        OvalShape1.FillColor = Color.DarkRed
    End Try

'Stop recording
Else
    OvalShape1.FillColor = Color.DarkRed

    Try
        'generate unique filename and save as tmp file
        Dim TempFullFileName As String = IO.Path.GetTempFileName()

        'save recording
        mciSendString("save recsound " & Chr(34) & TempFullFileName & Chr(34), "", 0, 0)
        mciSendString("close recsound", "", 0, 0)

        mciSendString("open " & Chr(34) & TempFullFileName & Chr(34) & " Alias recsound", "", 0, 0)
        mciSendString("play recsound", Nothing, 0, 0)
        mciSendString("close recsound", "", 0, 0)
    Catch ex As Exception
        MessageBox.Show(ex.ToString)
        OvalShape1.FillColor = Color.DarkRed
    End Try
End If

最初，我只是保存并播放了文件，接下来我关闭/重新打开了声音文件，但没有任何区别。我错过了什么吗？

谢谢。

编辑：

Try / catch不显示mciSendString返回的错误 - ＆gt;使用mciGetErrorString（）检查返回值
要播放整个声音文件，您必须在关闭之前添加“等待”

这是一些有效的代码：

Private Declare Function mciSendString Lib "winmm.dll" Alias "mciSendStringA" _
    (ByVal lpstrCommand As String, ByVal lpstrReturnString As String, _
     ByVal uReturnLength As Integer, ByVal hwndCallback As Integer) As Integer

Declare Function mciGetErrorString Lib "winmm.dll" Alias "mciGetErrorStringA" (ByVal dwError As Integer, ByVal lpstrBuffer As String, ByVal uLength As Integer) As Integer

Private Function GetMCIErrorString(ByVal ErrorCode As Integer) As String
    GetMCIErrorString = Space(1024)
    mciGetErrorString(ErrorCode, GetMCIErrorString, Len(GetMCIErrorString))
    GetMCIErrorString = Trim(GetMCIErrorString)
End Function

Private Sub Form1_DoubleClick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.DoubleClick

    Dim SoundFile As String = "C:\Documents and Settings\joe\Local Settings\Temp\tmp8FED.wav"
    SoundFile = ControlChars.Quote & SoundFile & ControlChars.Quote

    Dim StringToOpen As String = "open " & DummyFile & " alias recsound"
    ErrCode = mciSendString(StringToOpen, "", 0, 0)
    If ErrCode <> 0 Then
        MessageBox.Show(GetMCIErrorString(ErrCode))
        Exit Sub
    End If

    ErrCode = mciSendString("play recsound wait", Nothing, 0, 0)
    If ErrCode <> 0 Then
        MessageBox.Show(GetMCIErrorString(ErrCode))
        Exit Sub
    End If

    ErrCode = mciSendString("close recsound", "", 0, 0)
    If ErrCode <> 0 Then
        MessageBox.Show(GetMCIErrorString(ErrCode))
        Exit Sub
    End If
End Sub

无法播放WAV文件

0 个答案: