Question

我正在研究DVD刻录机器人。作为该过程的一部分，我需要打开和关闭DVD托盘，以允许机器人在刻录后拾取磁盘。然而，我遇到了一个问题。我只能在一台DVD录像机上控制弹出！因为我有两个这是一个问题。我一直在看这个小时，无法弄清楚出了什么问题。它可以控制1 DVD很好，但是当我在另一个类上实例化时它不起作用。这是下面的课程。我知道我可能会遗漏一些简单的东西，但对于我的生活，我无法理解它。

Public Class openCloseDrive
'Api call to send the commands to the mci device
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
'
'Api call to check for mci success or error
Private Declare Function mciGetErrorString Lib "winmm.dll" Alias _
    "mciGetErrorStringA" (ByVal dwError As Integer, ByVal lpstrBuffer _
        As String, ByVal uLength As Integer) As Integer

'will hold the mci return value
Dim retVal As Integer = Nothing

'This will contain the drive letter of the specified cd drive.
Dim _cdDrive As String = Nothing



Public Sub New(_driveLetter As String)
    _cdDrive = Chr(34) & _driveLetter & Chr(34)
End Sub

Public Function Open() As Integer
    'This will open the DVD Tray
    Dim retVal As Integer
    'This will Open the CD Drive Tray.
    mciSendString("open " & _cdDrive & " type cdaudio alias cd wait shareable", 0, 0, 0)
    retVal = mciSendString("set cd door open", 0, 0, 0)

    Return retVal
End Function

Public Function Close() As Integer
    'this Will close the DVD tray
    Dim retVal As Integer

    'This will Close the CD Drives Tray door.
    mciSendString("open " & _cdDrive & " type cdaudio alias cd wait shareable", 0, 0, 0)
    retVal = mciSendString("set cd door closed", 0, 0, 0)

    Return retVal
End Function


Public ReadOnly Property devices_InternalMCIStatus() As String
    '
    'Check the mci device to see if a error occured, and/or give 
    'some type of description even if everything was executed ok.
    '
    'Use this property if you want to, after each command you carried 
    'out to check and see if the command was successfully executed or 
    'not. It will tell you the status whether it was successful or not.
    '
    Get
        '
        'Make the length of this buffer 255 spaces since the returned
        'value could get pretty long, depending on what is going on.
        Dim buf As String = Space(255)

        mciGetErrorString(retVal, buf, 255)

        Return buf

        buf = Nothing

    End Get

End Property

结束班

Answer 1

我想我找到了解决方案。它是一个名为cdrecord.exe的命令行程序。通过向它发送命令行选项，打开和关闭托盘似乎没有问题！

打开和关闭多个驱动器

1 个答案: