VintaSoft Twain .NET SDK v10.2
Vintasoft.Twain Namespace / Device Class / StopFeeder Method
Example




In This Topic
    StopFeeder Method (Device)
    In This Topic
    Stops the automatic document feeder is possible.
    Syntax
    'Declaration
     
    Public Sub StopFeeder() 
    'Usage
     
    Dim instance As Device
     
    instance.StopFeeder()
    public void StopFeeder()
    public: void StopFeeder(); 
    public:
    void StopFeeder(); 
    Exceptions
    ExceptionDescription
    Thrown if device not in the DeviceState.TransferReady state.
    Thrown if feeder was not stopped.
    Thrown if the .NET debugger is used and the function evaluation requires all threads to run.
    Remarks
    Call this method only when the ImageAcquired event is fired.
    Example
    This example show how to pause the image acquisition from feeder (stop the feeder) and resume the image acquisition from feeder.
    Imports Vintasoft.Twain
                
    Class SyncScan_StopFeeder
                
        ''' <summary>
        ''' This method scans the first image, stops the document feeder,
        ''' scans the second image.
        ''' </summary>
        Public Shared Sub ScanImage_StopFeeder_ScanImage()
            Dim imageCount As Integer = 0
                
            ' create the device manager
            Using deviceManager As New DeviceManager()
                deviceManager.IsTwain2Compatible = True
                ' open the device manager
                deviceManager.Open()
                
                ' get the device
                Dim deviceName As String = "KODAK Scanner: i5000"
                Dim device As Device = deviceManager.Devices.Find(deviceName)
                If device Is Nothing Then
                    Throw New ApplicationException(String.Format("Device '{0}' is not found.", deviceName))
                End If
                
                ' disable device UI
                device.ShowUI = False
                ' specify that device must be closed after scan
                device.DisableAfterAcquire = True
                
                ' open the device
                device.Open()
                ' specify that 2 images must be acquired from scanner
                device.XferCount = 2
                
                ' run synchronous image acquisition
                Dim acquireModalState1 As AcquireModalState = AcquireModalState.None
                Do
                    acquireModalState1 = device.AcquireModal()
                    Select Case acquireModalState1
                        Case AcquireModalState.ImageAcquired
                            Console.WriteLine("Image is acquired.")
                            If device.AcquiredImage IsNot Nothing Then
                                device.AcquiredImage.Dispose()
                            End If
                
                            imageCount += 1
                
                            ' stop the feeder
                            device.StopFeeder()
                            Exit Select
                
                        Case AcquireModalState.ScanCompleted
                            Console.WriteLine("Scan is completed.")
                            Exit Select
                
                        Case AcquireModalState.ScanCanceled
                            Console.WriteLine("Scan is canceled.")
                            Exit Select
                
                        Case AcquireModalState.ScanFailed
                            Console.WriteLine(String.Format("Scan is failed: {0}.", device.ErrorString))
                            Exit Select
                    End Select
                Loop While acquireModalState1 <> AcquireModalState.None
                
                If imageCount <> 1 Then
                    Throw New ApplicationException("Wrong acquired image count.")
                End If
                
                If device.State <> DeviceState.TransferReady Then
                    Throw New ApplicationException("Feeder is NOT stopped.")
                End If
                Console.WriteLine("Feeder is stopped.")
                
                ' continue asynchronous image acquisition
                Do
                    acquireModalState1 = device.AcquireModal()
                    Select Case acquireModalState1
                        Case AcquireModalState.ImageAcquired
                            Console.WriteLine("Image is acquired.")
                
                            If device.AcquiredImage IsNot Nothing Then
                                device.AcquiredImage.Dispose()
                            End If
                
                            imageCount = imageCount + 1
                            Exit Select
                
                        Case AcquireModalState.ScanCompleted
                            Console.WriteLine("Scan is completed.")
                            Exit Select
                
                        Case AcquireModalState.ScanCanceled
                            Console.WriteLine("Scan is canceled.")
                            Exit Select
                
                        Case AcquireModalState.ScanFailed
                            Console.WriteLine(String.Format("Scan is failed: {0}.", device.ErrorString))
                            Exit Select
                    End Select
                Loop While acquireModalState1 <> AcquireModalState.None
                
                If imageCount <> 2 Then
                    Throw New ApplicationException("Wrong acquired image count.")
                End If
                
                ' close the device
                device.Close()
            End Using
        End Sub
                
    End Class
    using System;
    using Vintasoft.Twain;
                
    namespace TwainExamples_CSharp
    {
        class SyncScan_StopFeeder
        {
                
            /// <summary>
            /// This method scans the first image, stops the document feeder,
            /// scans the second image.
            /// </summary>
            public static void ScanImage_StopFeeder_ScanImage()
            {
                int imageCount = 0;
                
                // create the device manager
                using (DeviceManager deviceManager = new DeviceManager())
                {
                    deviceManager.IsTwain2Compatible = true;
                    // open the device manager
                    deviceManager.Open();
                
                    // get the device
                    string deviceName = "KODAK Scanner: i5000";
                    Device device = deviceManager.Devices.Find(deviceName);
                    if (device == null)
                        throw new ApplicationException(string.Format("Device '{0}' is not found.", deviceName));
                
                    // disable device UI
                    device.ShowUI = false;
                    // specify that device must be closed after scan
                    device.DisableAfterAcquire = true;
                
                    // open the device
                    device.Open();
                    // specify that 2 images must be acquired from scanner
                    device.XferCount = 2;
                
                    // run asynchronous image acquisition
                    AcquireModalState acquireModalState = AcquireModalState.None;
                    do
                    {
                        acquireModalState = device.AcquireModal();
                        switch (acquireModalState)
                        {
                            case AcquireModalState.ImageAcquired:
                                Console.WriteLine("Image is acquired.");
                                if (device.AcquiredImage != null)
                                    device.AcquiredImage.Dispose();
                
                                imageCount++;
                
                                // stop the feeder
                                device.StopFeeder();
                                break;
                
                            case AcquireModalState.ScanCompleted:
                                Console.WriteLine("Scan is completed.");
                                break;
                
                            case AcquireModalState.ScanCanceled:
                                Console.WriteLine("Scan is canceled.");
                                break;
                
                            case AcquireModalState.ScanFailed:
                                Console.WriteLine(string.Format("Scan is failed: {0}.", device.ErrorString));
                                break;
                        }
                    }
                    while (acquireModalState != AcquireModalState.None);
                
                    if (imageCount != 1)
                        throw new ApplicationException("Wrong acquired image count.");
                
                    if (device.State != DeviceState.TransferReady)
                        throw new ApplicationException("Feeder is NOT stopped.");
                    Console.WriteLine("Feeder is stopped.");
                
                    // continue asynchronous image acquisition
                    do
                    {
                        acquireModalState = device.AcquireModal();
                        switch (acquireModalState)
                        {
                            case AcquireModalState.ImageAcquired:
                                Console.WriteLine("Image is acquired.");
                
                                if (device.AcquiredImage != null)
                                    device.AcquiredImage.Dispose();
                
                                imageCount++;
                                break;
                
                            case AcquireModalState.ScanCompleted:
                                Console.WriteLine("Scan is completed.");
                                break;
                
                            case AcquireModalState.ScanCanceled:
                                Console.WriteLine("Scan is canceled.");
                                break;
                
                            case AcquireModalState.ScanFailed:
                                Console.WriteLine(string.Format("Scan is failed: {0}.", device.ErrorString));
                                break;
                        }
                    }
                    while (acquireModalState != AcquireModalState.None);
                
                    if (imageCount != 2)
                        throw new ApplicationException("Wrong acquired image count.");
                
                    // close the device
                    device.Close();
                }
            }
                
        }
    }
    Requirements

    Target Platforms: Windows 8, Windows 7, Windows Vista, Windows XP, Windows Server 2012, Windows Server 2008, Windows Server 2003

    See Also