Added most hooks except xfer logic and winform/wpf versions.

NTwain/TwainSessionWinform.cs

@@ -0,0 +1,39 @@
+using NTwain.Data;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Windows.Forms;
+using System.Windows.Interop;
+
+namespace NTwain
+{
+    /// <summary>
+    /// A customized TWAIN session for use in winform environment.
+    /// Use this by adding this as an <see cref="IMessageFilter "/> via <see cref="Application.AddMessageFilter"/>.
+    /// </summary>
+    public class TwainSessionWinform : TwainSessionBase, IMessageFilter
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="TwainSessionWinform" /> class.
+        /// </summary>
+        /// <param name="appId">The app id.</param>
+        /// <exception cref="System.ArgumentNullException"></exception>
+        public TwainSessionWinform(TWIdentity appId) : base(appId) { }
+
+        #region IMessageFilter Members
+
+        bool IMessageFilter.PreFilterMessage(ref Message m)
+        {
+            MSG winmsg = default(MSG);
+            winmsg.hwnd = m.HWnd;
+            winmsg.lParam = m.LParam;
+            winmsg.message = m.Msg;
+            winmsg.wParam = m.WParam;
+
+            return HandleWndProcMessage(ref winmsg);
+        }
+
+        #endregion
+    }
+}