/// <summary>
/// Synchronously acquires images from TWAIN device and saves images in a database.
/// </summary>
public void AcquireImagesFromTwainDeviceAndSaveImagesInDatabase()
{
    // create TWAIN device manager
    using (Vintasoft.Twain.DeviceManager deviceManager = new Vintasoft.Twain.DeviceManager())
    {
        // open TWAIN device manager
        deviceManager.Open();

        // get count of TWAIN devices
        int deviceCount = deviceManager.Devices.Count;
        if (deviceCount == 0)
        {
            System.Console.WriteLine("Devices are not found.");
            return;
        }

        // select the default TWAIN device
        Vintasoft.Twain.Device device = deviceManager.DefaultDevice;

        // open TWAIN device
        device.Open();

        System.IO.MemoryStream pdfDocumentInMemory = null;
        // acquire image(s) from the device
        Vintasoft.Twain.AcquireModalState acquireModalState;
        do
        {
            acquireModalState = device.AcquireModal();
            switch (acquireModalState)
            {
                case Vintasoft.Twain.AcquireModalState.ImageAcquired:
                    // if memory stream is empty
                    if (pdfDocumentInMemory == null)
                        // get the first image as PDF stored in the memory
                        pdfDocumentInMemory = device.AcquiredImage.GetAsStream(new Vintasoft.Twain.ImageEncoders.TwainPdfEncoderSettings());
                    else
                        // add image to PDF stored in the memory
                        device.AcquiredImage.Save(pdfDocumentInMemory, new Vintasoft.Twain.ImageEncoders.TwainPdfEncoderSettings());

                    device.AcquiredImage.Dispose();
                    break;

                case Vintasoft.Twain.AcquireModalState.ScanCompleted:
                    // save memory stream to a database
                    break;

                case Vintasoft.Twain.AcquireModalState.ScanCanceled:
                    // output current state
                    System.Console.WriteLine("Scan canceled.");
                    break;

                case Vintasoft.Twain.AcquireModalState.ScanFailed:
                    // output current state
                    System.Console.WriteLine(string.Format("Scan failed: {0}", device.ErrorString));
                    break;
            }
        }
        while (acquireModalState != Vintasoft.Twain.AcquireModalState.None);

        // close SANE device
        device.Close();

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

    System.Console.ReadLine();
}

''' <summary>
''' Synchronously acquires images from TWAIN device and saves images in a database.
''' </summary>
Public Sub AcquireImagesFromTwainDeviceAndSaveImagesInDatabase()
    ' create TWAIN device manager
    Using deviceManager As New Vintasoft.Twain.DeviceManager()
        ' open TWAIN device manager
        deviceManager.Open()

        ' get count of TWAIN devices
        Dim deviceCount As Integer = deviceManager.Devices.Count
        If deviceCount = 0 Then
            System.Console.WriteLine("Devices are not found.")
            Return
        End If

        ' select the default TWAIN device
        Dim device As Vintasoft.Twain.Device = deviceManager.DefaultDevice

        ' open TWAIN device
        device.Open()

        Dim pdfDocumentInMemory As System.IO.MemoryStream = Nothing
        ' acquire image(s) from the device
        Dim acquireModalState As Vintasoft.Twain.AcquireModalState
        Do
            acquireModalState = device.AcquireModal()
            Select Case acquireModalState
                Case Vintasoft.Twain.AcquireModalState.ImageAcquired
                    ' if memory stream is empty
                    If pdfDocumentInMemory Is Nothing Then
                        ' get the first image as PDF stored in the memory
                        pdfDocumentInMemory = device.AcquiredImage.GetAsStream(New Vintasoft.Twain.ImageEncoders.TwainPdfEncoderSettings())
                    Else
                        ' add image to PDF stored in the memory
                        device.AcquiredImage.Save(pdfDocumentInMemory, New Vintasoft.Twain.ImageEncoders.TwainPdfEncoderSettings())
                    End If

                    device.AcquiredImage.Dispose()
                    Exit Select

                Case Vintasoft.Twain.AcquireModalState.ScanCompleted
                    ' save memory stream to a database
                    Exit Select

                Case Vintasoft.Twain.AcquireModalState.ScanCanceled
                    ' output current state
                    System.Console.WriteLine("Scan canceled.")
                    Exit Select

                Case Vintasoft.Twain.AcquireModalState.ScanFailed
                    ' output current state
                    System.Console.WriteLine(String.Format("Scan failed: {0}", device.ErrorString))
                    Exit Select
            End Select
        Loop While acquireModalState <> Vintasoft.Twain.AcquireModalState.None

        ' close SANE device
        device.Close()

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

    System.Console.ReadLine()
End Sub