VintaSoft Twain .NET SDK 15.3: Documentation for .NET developer
In This Topic
    Cancel image acquisition from WIA image scanner
    In This Topic
    You should call the WiaDevice.Close method if you want to cancel the image acquisition from the automatic document feeder (ADF) of WIA image scanner.

    Here is an example that demonstrates how to cancel the current synchronous image transfer from WIA scanner:
    /// <summary>
    /// Acquires one image from WIA device and cancels image transfer.
    /// </summary>
    public static void AcquireOneImageFromWiaDeviceAndCancelScan()
    {
        // create WIA device manager
        using (Vintasoft.WiaImageScanning.WiaDeviceManager deviceManager = new Vintasoft.WiaImageScanning.WiaDeviceManager())
        {
            // open WIA device manager
            deviceManager.Open();
    
            // get count of WIA devices
            int deviceCount = deviceManager.Devices.Count;
            if (deviceCount == 0)
            {
                System.Console.WriteLine("Devices are not found.");
                return;
            }
    
            // select the first WIA device
            Vintasoft.WiaImageScanning.WiaDevice device = deviceManager.Devices[0];
    
            // open WIA device
            device.Open();
    
            Vintasoft.WiaImageScanning.WiaAcquiredImage acquiredImage;
            do
            {
                try
                {
                    // acquire image from WIA device
                    acquiredImage = device.AcquireImageSync();
                    // if image is received
                    if (acquiredImage != null)
                    {
                        System.Console.WriteLine("Image is acquired.");
    
                        // close the device
                        device.Close();
                    }
                    // 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 WIA device
            device.Close();
    
            // close WIA device manager
            deviceManager.Close();
        }
    
        System.Console.ReadLine();
    }
    
    ''' <summary>
    ''' Acquires one image from WIA device and cancels image transfer.
    ''' </summary>
    Public Shared Sub AcquireOneImageFromWiaDeviceAndCancelScan()
        ' create WIA device manager
        Using deviceManager As New Vintasoft.WiaImageScanning.WiaDeviceManager()
            ' open WIA device manager
            deviceManager.Open()
    
            ' get count of WIA 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 WIA device
            Dim device As Vintasoft.WiaImageScanning.WiaDevice = deviceManager.Devices(0)
    
            ' open WIA device
            device.Open()
    
            Dim acquiredImage As Vintasoft.WiaImageScanning.WiaAcquiredImage
            Do
                Try
                    ' acquire image from WIA device
                    acquiredImage = device.AcquireImageSync()
                    ' if image is received
                    If acquiredImage IsNot Nothing Then
                        System.Console.WriteLine("Image is acquired.")
    
                        ' close the device
                        device.Close()
                    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 WIA device
            device.Close()
    
            ' close WIA device manager
            deviceManager.Close()
        End Using
    
        System.Console.ReadLine()
    End Sub