Binaryworld - ExecuteMCICommand - Executing a MCI command ... [ VB.net -> Multimedia ]

<System.Runtime.InteropServices.DllImport("winmm.dll")> Shared Function _
  mciSendString(ByVal lpstrCommand As String, ByVal lpstrReturnString As _
  String, ByVal uReturnLength As Integer, ByVal hwndCallback As Integer) As _
  Integer
End Function

' helper routine; executes a MCI command
' commandString is the command to execute
' deviceAlreadyOpened must be set to true if the caller has already opened the
' device

Sub ExecuteMCICommand(ByVal commandString As String, ByVal deviceAlreadyOpened _
  As Boolean)
  Dim returnCode As Integer = mciSendString(commandString, vbNullString, 0, 0)

  ' if the return code is not 0, an error occurred
  If returnCode <> 0 Then

    ' close the device if necessary
    If deviceAlreadyOpened Then
      commandString = "close AVIFile"
      mciSendString(commandString, vbNullString, 0, 0)
    End If

    ' throw a custom exception
    Throw New MCICommandException(returnCode)

  End If
End Sub

' helper custom exception
' motes: requires the GetMCIErrorString function

Class MCICommandException
  Inherits Exception

  Public Sub New(ByVal errorCode As Integer)
    MyBase.New(GetMCIErrorString(errorCode))
  End Sub
End Class