Vb.net 如何在Twain UI中关闭设备

我有目前的问题。使用Twain UI，如果单击“取消”，则不会出现捕获异常，也不会关闭设备。如果我再次打开UI并单击“扫描”，它将不允许我打开设备，它将保持关闭状态，当前例外情况为：设备未打开错误代码：11

    Public Sub AcquireImage()
    OpenDeviceManager()
    Dim device As Vintasoft.Twain.Device = devManager.Devices.Find("KODAK Scanner: i1150/i1180")

    Try
        snCount = 0
        imgCount = 0

        device.ShowUI = True
        device.Open() ''PROBLEM IS HERE


        device.PixelType = PixelType.Gray
        device.Acquire()

        AddHandler device.ImageAcquired, AddressOf device_ImageAcquired
        AddHandler device.ScanCompleted, AddressOf device_ScanCompleted
        AddHandler device.ScanCanceled, AddressOf device_ScanCanceled
        AddHandler device.ScanFailed, AddressOf device_ScanFailed

        device.DisableAfterAcquire = True


    Catch ex As TwainException
        MessageBox.Show(ex.Message) '' Device is not opened Error code: 11
        CloseDevice(device)

        device.Disable()



        Return
    End Try



End Sub

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我可以扫描任意次数，但我希望在UI上使用“取消”，设备状态不会更改值。

我通过添加设备的添加和删除处理程序解决了问题。UserInterfaceClosed。

Private Sub AcquireImage()
    SetFormUiState(False)
    OpenDeviceManager()
    Dim device As Vintasoft.Twain.Device = devManager.Devices.Find("KODAK Scanner: i1150/i1180")

    Try

        AddHandler device.ImageAcquired, AddressOf device_ImageAcquired
        AddHandler device.ScanCompleted, AddressOf device_ScanCompleted
        AddHandler device.ScanCanceled, AddressOf device_ScanCanceled
        AddHandler device.ScanFailed, AddressOf device_ScanFailed
        **AddHandler device.UserInterfaceClosed, AddressOf device_UserInterfaceClosed**

        snCount = 0
        imgCount = 0

        device.Open()
        device.ShowUI = True
        device.PixelType = PixelType.Gray
        device.Acquire()
        device.DisableAfterAcquire = True

    Catch ex As TwainException
        MessageBox.Show(ex.Message)
        SetFormUiState(True)
        CloseDevice(device)
        Return
    End Try
End Sub