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vb.nettwain

How to close device in Twain UI

I am having the current problem. Using the Twain UI if I click on cancel it is not going to the catch exception and is not closing the device. If I once more open the UI and click on scan it does not let me open the device it stays closed with the current exception of: Device is not open Error code: 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

enter image description here enter image description here

I can scan as many times I want but I would like to use the Cancel on the UI the device Status does not change values.

Solution

  • I solved the problem by adding the add and remove handler for device.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