Cleaned up wpf sample with some view models.

Tests/Tester.WPF/TwainVM.cs

@@ -0,0 +1,96 @@
+using NTwain;
+using NTwain.Data;
+using NTwain.Values;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Reflection;
+using System.Text;
+using System.Windows.Media;
+using System.Windows.Media.Imaging;
+using CommonWin32;
+using System.Threading;
+
+namespace Tester.WPF
+{
+    /// <summary>
+    /// Wraps the twain session as a view model for databinding.
+    /// </summary>
+    class TwainVM : TwainSessionWPF
+    {
+        public TwainVM()
+            : base(TWIdentity.CreateFromAssembly(DataGroups.Image | DataGroups.Audio, Assembly.GetEntryAssembly()))
+        {
+
+        }
+
+        private ImageSource _image;
+
+        /// <summary>
+        /// Gets or sets the captured image.
+        /// </summary>
+        /// <value>
+        /// The image.
+        /// </value>
+        public ImageSource Image
+        {
+            get { return _image; }
+            set
+            {
+                _image = value;
+                RaisePropertyChanged("Image");
+            }
+        }
+
+        protected override void OnTransferReady(TransferReadyEventArgs e)
+        {
+            // set it up to use file xfer
+
+            if (this.GetCurrentCap<XferMech>(CapabilityId.ICapXferMech) == XferMech.File)
+            {
+                var formats = this.CapGetImageFileFormat();
+                var wantFormat = formats.Contains(FileFormat.Tiff) ? FileFormat.Tiff : FileFormat.Bmp;
+
+                var fileSetup = new TWSetupFileXfer
+                {
+                    Format = wantFormat,
+                    FileName = System.IO.Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Desktop), "test.tif")
+                };
+                var rc = this.DGControl.SetupFileXfer.Set(fileSetup);
+            }
+            base.OnTransferReady(e);
+        }
+
+        protected override void OnDataTransferred(DataTransferredEventArgs e)
+        {
+            if (e.Data != IntPtr.Zero)
+            {
+                Image = e.Data.GetWPFBitmap();
+            }
+            else if (!string.IsNullOrEmpty(e.FilePath))
+            {
+                var img = new BitmapImage(new Uri(e.FilePath));
+                Image = img;
+            }
+            base.OnDataTransferred(e);
+        }
+
+        public void TestCapture(IntPtr hwnd)
+        {
+            if (State == 4)
+            {
+                if (this.CapGetPixelTypes().Contains(PixelType.BlackWhite))
+                {
+                    this.CapSetPixelType(PixelType.BlackWhite);
+                }
+
+                if (this.CapGetImageXferMechs().Contains(XferMech.File))
+                {
+                    this.CapSetImageXferMech(XferMech.File);
+                }
+
+                var rc = EnableSource(SourceEnableMode.NoUI, false, hwnd, SynchronizationContext.Current);
+            }
+        }
+    }
+}