以下VB代码，求牛人~

写了一段播放器代码，但是总是放不出来，也不报错，谁能看出哪里有问题吗？Private Sub mnuOpen_Click() Dim temp As Integer Dim stringtext As String Dim midx, midy As Double cmdOpen.FileName = "" cmdOpen.Filter = "avi文件(*.avi)|*.avi|dat文件(*.dat)|*.dat|" cmdOpen.FilterIndex = 2 cmdOpen.DialogTitle = "打开媒体文件" cmdOpen.Action = 1 MMControl1.Command = "close" If cmdOpen.FileName = "" Then temp = MsgBox("没有选择文件", 37, "检查") ElseIf cmdOpen.FilterIndex = 1 Then MMControl1.DeviceType = "AviVideo" MMControl1.TimeFormat = 3 MMControl1.FileName = cmdOpen.FileName MMControl1.Command = "open" MMControl1.hWndDisplay = picture1.hWnd Slider1.Min = 0 Slider1.Max = MMControl1.Length + 1 ElseIf cmdOpen.FilterIndex = 2 Then MMControl1.DeviceType = "mpegvideo" MMControl1.TimeFormat = 3 MMControl1.FileName = cmdOpen.FileName MMControl1.Command = "open" MMControl1.hWndDisplay = picture1.hWnd Slider1.Min = 0 Slider1.Max = MMControl1.Length End IfEnd Sub