VintaSoft Twain .NET SDK 15.4: Documentation for .NET developer
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Cancel image acquisition from eSCL scanner
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You should call the EsclDevice.CancelImageTransfer method if you want to cancel the image acquisition from the automatic document feeder (ADF) of eSCL scanner.

Here is an example that demonstrates how to cancel the current synchronous image transfer from eSCL scanner:
/// <summary>
/// Acquires one image from eSCL device and cancels image transfer.
/// </summary>
public static void AcquireOneImageFromEsclDeviceAndCancelScan()
{
    // create eSCL device manager
    using (Vintasoft.EsclImageScanning.EsclDeviceManager deviceManager = new Vintasoft.EsclImageScanning.EsclDeviceManager())
    {
        // open eSCL device manager
        deviceManager.Open();

        // wait while the eSCL device manager searches for eSCL devices
        System.Threading.Thread.Sleep(deviceManager.DeviceSearchTimeout);
        // get count of eSCL devices
        int deviceCount = deviceManager.Devices.Count;
        if (deviceCount == 0)
        {
            System.Console.WriteLine("Devices are not found.");
            return;
        }

        // select the first eSCL device
        Vintasoft.EsclImageScanning.EsclDevice device = deviceManager.Devices[0];

        // open eSCL device
        device.Open();

        Vintasoft.EsclImageScanning.EsclAcquiredImage acquiredImage;
        do
        {
            try
            {
                // acquire image from eSCL device
                acquiredImage = device.AcquireImageSync();
                // if image is received
                if (acquiredImage != null)
                {
                    System.Console.WriteLine("Image is acquired.");

                    // cancel image transfer
                    device.CancelImageTransfer();
                }
                // if image is not received
                else
                {
                    System.Console.WriteLine("Scan is completed.");
                    break;
                }
            }
            catch (System.Exception ex)
            {
                System.Console.WriteLine(string.Format("Scan is failed: {0}", ex.Message));
                break;
            }
        }
        // while image is acquired
        while (acquiredImage != null);

        // close eSCL device
        device.Close();

        // close eSCL device manager
        deviceManager.Close();
    }

    System.Console.ReadLine();
}
''' <summary>
''' Acquires one image from eSCL device and cancels image transfer.
''' </summary>
Public Shared Sub AcquireOneImageFromEsclDeviceAndCancelScan()
    ' create eSCL device manager
    Using deviceManager As New Vintasoft.EsclImageScanning.EsclDeviceManager()
        ' open eSCL device manager
        deviceManager.Open()

        ' wait while the eSCL device manager searches for eSCL devices
        System.Threading.Thread.Sleep(deviceManager.DeviceSearchTimeout)
        ' get count of eSCL devices
        Dim deviceCount As Integer = deviceManager.Devices.Count
        If deviceCount = 0 Then
            System.Console.WriteLine("Devices are not found.")
            Return
        End If

        ' select the first eSCL device
        Dim device As Vintasoft.EsclImageScanning.EsclDevice = deviceManager.Devices(0)

        ' open eSCL device
        device.Open()

        Dim acquiredImage As Vintasoft.EsclImageScanning.EsclAcquiredImage
        Do
            Try
                ' acquire image from eSCL device
                acquiredImage = device.AcquireImageSync()
                ' if image is received
                If acquiredImage IsNot Nothing Then
                    System.Console.WriteLine("Image is acquired.")

                    ' cancel image transfer
                    device.CancelImageTransfer()
                Else
                    ' if image is not received
                    System.Console.WriteLine("Scan is completed.")
                    Exit Try
                End If
            Catch ex As System.Exception
                System.Console.WriteLine(String.Format("Scan is failed: {0}", ex.Message))
                Exit Try
            End Try
            ' while image is acquired
        Loop While acquiredImage IsNot Nothing

        ' close eSCL device
        device.Close()

        ' close eSCL device manager
        deviceManager.Close()
    End Using

    System.Console.ReadLine()
End Sub