VintaSoft Twain .NET SDK 14.1: Руководство для .NET разработчика
В этом разделе
    Отмена получения изображений от SANE сканера
    В этом разделе
    Нужно вызвать метод SaneLocalDevice.CancelImageTransfer, если необходимо отменить получение изображений от SANE сканера.


    Вот C#/VB.NET код, который демонстрирует, как отменить синхронную передачу изображений от SANE сканера:
    /// <summary>
    /// Acquires one image from SANE device and cancels image transfer.
    /// </summary>
    public static void AcquireOneImageFromSaneDeviceAndCancelScan()
    {
        // create SANE device manager
        using (Vintasoft.Sane.SaneLocalDeviceManager deviceManager = new Vintasoft.Sane.SaneLocalDeviceManager())
        {
            // open SANE device manager
            deviceManager.Open();
    
            // get count of SANE devices
            int deviceCount = deviceManager.Devices.Count;
            if (deviceCount == 0)
            {
                System.Console.WriteLine("Devices are not found.");
                return;
            }
    
            // select the first SANE device
            Vintasoft.Sane.SaneLocalDevice device = deviceManager.Devices[0];
    
            // open SANE device
            device.Open();
    
            Vintasoft.Sane.SaneAcquiredImage acquiredImage;
            do
            {
                try
                {
                    // acquire image from SANE 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 device has more images to scan
            while (device.HasMoreImagesToScan);
    
            // close SANE device
            device.Close();
    
            // close SANE device manager
            deviceManager.Close();
        }
    
        System.Console.ReadLine();
    }
    
    ''' <summary>
    ''' Acquires one image from SANE device and cancels image transfer.
    ''' </summary>
    Public Shared Sub AcquireOneImageFromSaneDeviceAndCancelScan()
            ' create SANE device manager
            Using deviceManager As New Vintasoft.Sane.SaneLocalDeviceManager()
                    ' open SANE device manager
                    deviceManager.Open()
    
                    ' get count of SANE 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 SANE device
                    Dim device As Vintasoft.Sane.SaneLocalDevice = deviceManager.Devices(0)
    
                    ' open SANE device
                    device.Open()
    
                    Dim acquiredImage As Vintasoft.Sane.SaneAcquiredImage
                    Do
                            Try
                                    ' acquire image from SANE 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 device has more images to scan
                    Loop While device.HasMoreImagesToScan
    
                    ' close SANE device
                    device.Close()
    
                    ' close SANE device manager
                    deviceManager.Close()
            End Using
    
            System.Console.ReadLine()
    End Sub