VintaSoft Twain .NET SDK 15.2: Documentation for .NET developer
In This Topic
    Cancel image acquisition from eSCL scanner
    In This Topic
    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