我有以下代码：
http://pastebin.com/EgjbzqA2基本上只是
http://www.dreamincode.net/forums/topic/57357-mymusic-player/的精简版本.我希望程序重复播放一个文件,但是,此功能由于某种原因不起作用.程序播放每个文件一次然后停止.
Private Sub Player3_PlayStateChange(ByVal NewState As Integer) Handles Player3.PlayStateChange
Static Dim PlayAllowed As Boolean = True
Select Case CType(NewState,WMPLib.WMPPlayState)
Case WMPLib.WMPPlayState.wmppsReady
If PlayAllowed Then
Player3.controls.play()
End If
Case WMPLib.WMPPlayState.wmppsMediaEnded
' Start protection (without it next wouldn't play
PlayAllowed = False
' Play track
Player3.controls.play()
' End Protection
PlayAllowed = True
updatePlayer()
End Select
End Sub
当你要求它在事件中做其他事情时,PlayAllowed doo-wop是hackorama来解决控制变得暴躁的问题.这往往是错误的,他们不希望地板垫在发生事件时被猛拉.技术术语是它们不能很好地处理重入,这是一个非常普遍的问题.
对于重新入侵问题有一个非常优雅的解决方案,关键是在事件发生后你再次延迟播放同一首歌的请求.在Winforms中,您可以通过使用Control.BeginInvoke()轻松获得此类延迟,目标在所有内容恢复后运行.技术术语是“等待程序重新进入消息循环”.在这段代码上运行得非常好,我在使用此代码时反复循环播放同一首歌,并在Windows 8上进行了测试：
Public Class Form1
Dim WithEvents Player3 As New WMPLib.WindowsMediaPlayer
Dim Song As String = "c:\temp\ding.wav"
Private Sub Button1_Click(ByVal sender As System.Object,ByVal e As System.EventArgs) Handles Button1.Click
PlayCurrentSong()
End Sub
Private Sub Player3_PlayStateChange(ByVal NewState As Integer) Handles Player3.PlayStateChange
If NewState = WMPLib.WMPPlayState.wmppsMediaEnded Then
Me.BeginInvoke(New MethodInvoker(AddressOf PlayCurrentSong))
End If
End Sub
Private Sub PlayCurrentSong()
Player3.URL = Song
Player3.controls.play()
End Sub
End Class
根据需要调整代码,因为它与您的代码不相符.关键部分是PlayStateChanged事件处理程序中的Me.BeginInvoke()调用.