Added DG triplet placeholders.

samples/NetCoreConsole/Program.cs

@@ -13,11 +13,22 @@ namespace NetCoreConsole
                 .Build();
             using (var session = new TwainSession(config))
             {
+                session.PropertyChanged += Session_PropertyChanged;
+
+                var handle = IntPtr.Zero;
+                session.Open(ref handle);
 
             }
 
+        }
 
-            Console.WriteLine("Hello World!");
+        private static void Session_PropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
+        {
+            var session = (TwainSession)sender;
+            if (e.PropertyName == "State")
+            {
+                Console.WriteLine($"State changed to {session.State}");
+            }
         }
     }
 }

src/NTwain/Data/TwainTypes.cs

@@ -27,14 +27,6 @@ using TW_UINT8 = System.Byte;    // unsigned char
 // http://www.mono-project.com/Interop_with_Native_Libraries (old)
 // http://www.mono-project.com/docs/advanced/pinvoke/ (new url)
 
-//////////////////////////////////
-// Data structures that
-// are passed to the TWAIN method
-// are defined as classes to reduce
-// ref/out in the low-level calls. 
-// Others continue to be structs.
-//////////////////////////////////
-
 
 namespace NTwain.Data
 {
@@ -241,7 +233,7 @@ namespace NTwain.Data
         TW_MEMREF _context;
 
         [FieldOffset(520)] // not sure why it should be 520 but whatev
-        Int32 Recursive;
+        Int32 _recursive;
         [FieldOffset(520)]
         TW_BOOL _subdirectories;
 

src/NTwain/Data/TwainTypesExtended.cs

@@ -1419,8 +1419,8 @@ namespace NTwain.Data
         /// </summary>
         public bool Recursive
         {
-            get { return _subdirectories == TwainConst.True; }
+            get { return _recursive == 1; }
-            set { _subdirectories = value ? TwainConst.True : TwainConst.False; }
+            set { _recursive = value ? 1 : 0; }
         }
 
         /// <summary>
@@ -1688,7 +1688,6 @@ namespace NTwain.Data
             internal set { _supportedGroups = ((uint)value & 0xffff0000) | (0x0000ffff & _supportedGroups); }
         }
 
-
         public string Manufacturer
         {
             get { return _manufacturer; }

src/NTwain/NTwain.csproj

@@ -21,10 +21,6 @@
     <Version>4.0.0</Version>
   </PropertyGroup>
 
-  <ItemGroup>
-    <Folder Include="Triplets\" />
-  </ItemGroup>
-
   <ItemGroup>
     <Compile Update="Resources\MsgText.Designer.cs">
       <DesignTime>True</DesignTime>

src/NTwain/Triplets/BaseTriplet.cs

@@ -0,0 +1,12 @@
+namespace NTwain.Triplets
+{
+    public abstract class BaseTriplet
+    {
+        protected TwainSession session;
+
+        public BaseTriplet(TwainSession session)
+        {
+            this.session = session;
+        }
+    }
+}

src/NTwain/Triplets/DGAudio.cs

@@ -0,0 +1,13 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace NTwain.Triplets
+{
+    public partial class DGAudio : BaseTriplet
+    {
+        internal DGAudio(TwainSession session) : base(session) { }
+
+    }
+}

src/NTwain/Triplets/DGControl.Parent.cs

@@ -0,0 +1,27 @@
+using NTwain.Data;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace NTwain.Triplets
+{
+    public partial class Parent : BaseTriplet
+    {
+        internal Parent(TwainSession session) : base(session) { }
+
+        public ReturnCode OpenDSM(ref IntPtr hWnd)
+        {
+            var rc = NativeMethods.DsmWin32(session.Config.AppWin32, null, DataGroups.Control, DataArgumentType.Parent, Message.OpenDSM, ref hWnd);
+            if (rc == ReturnCode.Success) session.State = TwainState.DsmOpened;
+            return rc;
+        }
+
+        public ReturnCode CloseDSM(ref IntPtr hWnd)
+        {
+            var rc = NativeMethods.DsmWin32(session.Config.AppWin32, null, DataGroups.Control, DataArgumentType.Parent, Message.CloseDSM, ref hWnd);
+            if (rc == ReturnCode.Success) session.State = TwainState.DsmLoaded;
+            return rc;
+        }
+    }
+}

src/NTwain/Triplets/DGControl.cs

@@ -0,0 +1,15 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace NTwain.Triplets
+{
+    public partial class DGControl : BaseTriplet
+    {
+        internal DGControl(TwainSession session) : base(session) { }
+
+        Parent _parent;
+        internal Parent Parent => _parent ?? (_parent = new Parent(session));
+    }
+}

src/NTwain/Triplets/DGCustom.cs

@@ -0,0 +1,13 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace NTwain.Triplets
+{
+    public partial class DGCustom : BaseTriplet
+    {
+        internal DGCustom(TwainSession session) : base(session) { }
+
+    }
+}

src/NTwain/Triplets/DGImage.cs

@@ -0,0 +1,13 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace NTwain.Triplets
+{
+    public partial class DGImage : BaseTriplet
+    {
+        internal DGImage(TwainSession session) : base(session) { }
+
+    }
+}

src/NTwain/Triplets/NativeMethods.Win32.cs

@@ -0,0 +1,283 @@
+using NTwain.Data;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Runtime.InteropServices;
+using System.Text;
+
+namespace NTwain.Triplets
+{
+    static partial class NativeMethods
+    {
+        [DllImport(WinDsmDll, EntryPoint = EntryName)]
+        public static extern ReturnCode DsmWin32(
+            [In, Out]TW_IDENTITY origin,
+            [In, Out]TW_IDENTITY destination,
+            DataGroups dg,
+            DataArgumentType dat,
+            Message msg,
+            ref IntPtr data);
+
+        [DllImport(WinDsmDll, EntryPoint = EntryName)]
+        public static extern ReturnCode DsmWin32(
+            [In, Out]TW_IDENTITY origin,
+            [In, Out]TW_IDENTITY destination,
+            DataGroups dg,
+            DataArgumentType dat,
+            Message msg,
+            ref DataGroups data);
+
+        [DllImport(WinDsmDll, EntryPoint = EntryName)]
+        public static extern ReturnCode DsmWin32(
+            [In, Out]TW_IDENTITY origin,
+            [In, Out]TW_IDENTITY destination,
+            DataGroups dg,
+            DataArgumentType dat,
+            Message msg,
+            ref TW_AUDIOINFO data);
+
+        //[DllImport(DSM.WinDsmDll, EntryPoint = DSM.EntryName)]
+        //public static extern ReturnCode DsmWin32(
+        //    [In, Out]TW_IDENTITY origin,
+        //    [In, Out]TW_IDENTITY destination,
+        //    DataGroups dg,
+        //    DataArgumentType dat,
+        //    Message msg,
+        //    ref TWCapability data);
+
+        [DllImport(WinDsmDll, EntryPoint = EntryName)]
+        public static extern ReturnCode DsmWin32(
+            [In, Out]TW_IDENTITY origin,
+            [In, Out]TW_IDENTITY destination,
+            DataGroups dg,
+            DataArgumentType dat,
+            Message msg,
+            ref TW_CUSTOMDSDATA data);
+
+        [DllImport(WinDsmDll, EntryPoint = EntryName)]
+        public static extern ReturnCode DsmWin32(
+            [In, Out]TW_IDENTITY origin,
+            [In, Out]TW_IDENTITY destination,
+            DataGroups dg,
+            DataArgumentType dat,
+            Message msg,
+            ref TW_DEVICEEVENT data);
+
+        [DllImport(WinDsmDll, EntryPoint = EntryName)]
+        public static extern ReturnCode DsmWin32(
+            [In, Out]TW_IDENTITY origin,
+            [In, Out]TW_IDENTITY destination,
+            DataGroups dg,
+            DataArgumentType dat,
+            Message msg,
+            ref TW_CALLBACK data);
+
+        [DllImport(WinDsmDll, EntryPoint = EntryName)]
+        public static extern ReturnCode DsmWin32(
+            [In, Out]TW_IDENTITY origin,
+            [In, Out]TW_IDENTITY destination,
+            DataGroups dg,
+            DataArgumentType dat,
+            Message msg,
+            ref TW_CALLBACK2 data);
+
+        [DllImport(WinDsmDll, EntryPoint = EntryName)]
+        public static extern ReturnCode DsmWin32(
+            [In, Out]TW_IDENTITY origin,
+            [In, Out]TW_IDENTITY destination,
+            DataGroups dg,
+            DataArgumentType dat,
+            Message msg,
+            ref TW_ENTRYPOINT data);
+
+        [DllImport(WinDsmDll, EntryPoint = EntryName)]
+        public static extern ReturnCode DsmWin32(
+            [In, Out]TW_IDENTITY origin,
+            [In, Out]TW_IDENTITY destination,
+            DataGroups dg,
+            DataArgumentType dat,
+            Message msg,
+            ref TW_EVENT data);
+
+        [DllImport(WinDsmDll, EntryPoint = EntryName)]
+        public static extern ReturnCode DsmWin32(
+            [In, Out]TW_IDENTITY origin,
+            [In, Out]TW_IDENTITY destination,
+            DataGroups dg,
+            DataArgumentType dat,
+            Message msg,
+            ref TW_FILESYSTEM data);
+
+        [DllImport(WinDsmDll, EntryPoint = EntryName)]
+        public static extern ReturnCode DsmWin32(
+            [In, Out]TW_IDENTITY origin,
+            IntPtr zero,
+            DataGroups dg,
+            DataArgumentType dat,
+            Message msg,
+            [In, Out]TW_IDENTITY data);
+
+        [DllImport(WinDsmDll, EntryPoint = EntryName)]
+        public static extern ReturnCode DsmWin32(
+            [In, Out]TW_IDENTITY origin,
+            [In, Out]TW_IDENTITY destination,
+            DataGroups dg,
+            DataArgumentType dat,
+            Message msg,
+            ref TW_PASSTHRU data);
+
+        [DllImport(WinDsmDll, EntryPoint = EntryName)]
+        public static extern ReturnCode DsmWin32(
+            [In, Out]TW_IDENTITY origin,
+            [In, Out]TW_IDENTITY destination,
+            DataGroups dg,
+            DataArgumentType dat,
+            Message msg,
+            ref TW_PENDINGXFERS data);
+
+        [DllImport(WinDsmDll, EntryPoint = EntryName)]
+        public static extern ReturnCode DsmWin32(
+            [In, Out]TW_IDENTITY origin,
+            [In, Out]TW_IDENTITY destination,
+            DataGroups dg,
+            DataArgumentType dat,
+            Message msg,
+            ref TW_SETUPFILEXFER data);
+
+        [DllImport(WinDsmDll, EntryPoint = EntryName)]
+        public static extern ReturnCode DsmWin32(
+            [In, Out]TW_IDENTITY origin,
+            [In, Out]TW_IDENTITY destination,
+            DataGroups dg,
+            DataArgumentType dat,
+            Message msg,
+            ref TW_SETUPMEMXFER data);
+
+        [DllImport(WinDsmDll, EntryPoint = EntryName)]
+        public static extern ReturnCode DsmWin32(
+            [In, Out]TW_IDENTITY origin,
+            [In, Out]TW_IDENTITY destination,
+            DataGroups dg,
+            DataArgumentType dat,
+            Message msg,
+            ref TW_STATUSUTF8 data);
+
+        [DllImport(WinDsmDll, EntryPoint = EntryName)]
+        public static extern ReturnCode DsmWin32(
+            [In, Out]TW_IDENTITY origin,
+            [In, Out]TW_IDENTITY destination,
+            DataGroups dg,
+            DataArgumentType dat,
+            Message msg,
+            ref TW_USERINTERFACE data);
+
+        [DllImport(WinDsmDll, EntryPoint = EntryName)]
+        public static extern ReturnCode DsmWin32(
+            [In, Out]TW_IDENTITY origin,
+            [In, Out]TW_IDENTITY destination,
+            DataGroups dg,
+            DataArgumentType dat,
+            Message msg,
+            ref TW_CIECOLOR data);
+
+        [DllImport(WinDsmDll, EntryPoint = EntryName)]
+        public static extern ReturnCode DsmWin32(
+            [In, Out]TW_IDENTITY origin,
+            [In, Out]TW_IDENTITY destination,
+            DataGroups dg,
+            DataArgumentType dat,
+            Message msg,
+            ref TW_EXTIMAGEINFO data);
+
+        [DllImport(WinDsmDll, EntryPoint = EntryName)]
+        public static extern ReturnCode DsmWin32(
+            [In, Out]TW_IDENTITY origin,
+            [In, Out]TW_IDENTITY destination,
+            DataGroups dg,
+            DataArgumentType dat,
+            Message msg,
+            ref TW_FILTER data);
+
+        //[DllImport(DSM.WinDsmDll, EntryPoint = DSM.EntryName)]
+        //public static extern ReturnCode DsmWin32(
+        //    [In, Out]TW_IDENTITY origin,
+        //    [In, Out]TW_IDENTITY destination,
+        //    DataGroups dg,
+        //    DataArgumentType dat,
+        //    Message msg,
+        //    ref TWGrayResponse data);
+
+        [DllImport(WinDsmDll, EntryPoint = EntryName)]
+        public static extern ReturnCode DsmWin32(
+            [In, Out]TW_IDENTITY origin,
+            [In, Out]TW_IDENTITY destination,
+            DataGroups dg,
+            DataArgumentType dat,
+            Message msg,
+            ref TW_IMAGEINFO data);
+
+        [DllImport(WinDsmDll, EntryPoint = EntryName)]
+        public static extern ReturnCode DsmWin32(
+            [In, Out]TW_IDENTITY origin,
+            [In, Out]TW_IDENTITY destination,
+            DataGroups dg,
+            DataArgumentType dat,
+            Message msg,
+            ref TW_IMAGELAYOUT data);
+
+        [DllImport(WinDsmDll, EntryPoint = EntryName)]
+        public static extern ReturnCode DsmWin32(
+            [In, Out]TW_IDENTITY origin,
+            [In, Out]TW_IDENTITY destination,
+            DataGroups dg,
+            DataArgumentType dat,
+            Message msg,
+            ref TW_IMAGEMEMXFER data);
+
+        [DllImport(WinDsmDll, EntryPoint = EntryName)]
+        public static extern ReturnCode DsmWin32(
+            [In, Out]TW_IDENTITY origin,
+            [In, Out]TW_IDENTITY destination,
+            DataGroups dg,
+            DataArgumentType dat,
+            Message msg,
+            ref TW_JPEGCOMPRESSION data);
+
+        [DllImport(WinDsmDll, EntryPoint = EntryName)]
+        public static extern ReturnCode DsmWin32(
+            [In, Out]TW_IDENTITY origin,
+            [In, Out]TW_IDENTITY destination,
+            DataGroups dg,
+            DataArgumentType dat,
+            Message msg,
+            ref TW_PALETTE8 data);
+
+        //[DllImport(DSM.WinDsmDll, EntryPoint = DSM.EntryName)]
+        //public static extern ReturnCode DsmWin32(
+        //    [In, Out]TW_IDENTITY origin,
+        //    [In, Out]TW_IDENTITY destination,
+        //    DataGroups dg,
+        //    DataArgumentType dat,
+        //    Message msg,
+        //    ref TWRgbResponse data);
+
+        [DllImport(WinDsmDll, EntryPoint = EntryName)]
+        public static extern ReturnCode DsmWin32(
+            [In, Out]TW_IDENTITY origin,
+            [In, Out]TW_IDENTITY destination,
+            DataGroups dg,
+            DataArgumentType dat,
+            Message msg,
+            ref TW_STATUS data);
+
+        [DllImport(WinDsmDll, EntryPoint = EntryName)]
+        public static extern ReturnCode DsmWin32(
+            [In, Out]TW_IDENTITY origin,
+            [In, Out]TW_IDENTITY destination,
+            DataGroups dg,
+            DataArgumentType dat,
+            Message msg,
+            ref TW_MEMORY data);
+
+    }
+}

src/NTwain/Triplets/NativeMethods.cs

@@ -0,0 +1,18 @@
+using NTwain.Data;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace NTwain.Triplets
+{
+    static partial class NativeMethods
+    {
+        const string EntryName = "DSM_Entry";
+
+        const string WinDsmDll = "twaindsm.dll";
+        const string LinuxDsmDll = "/usr/local/lib/libtwaindsm.so";
+        const string MacDsmDll = "/Library/Frameworks/TWAINDSM.framework/TWAINDSM";
+
+    }
+}

src/NTwain/TwainConfig.cs

@@ -13,9 +13,11 @@ namespace NTwain
     {
         internal TwainConfig() { }
 
-        public bool PreferLegacyDsm { get; internal set; }
+        //public bool PreferLegacyDsm { get; internal set; }
 
-        public ITW_IDENTITY App { get; internal set; }
+        internal TW_IDENTITY AppWin32 { get; set; }
+
+        internal TW_IDENTITY SrcWin32 { get; set; }
 
         internal IMemoryManager MemoryManager { get; set; }
     }

src/NTwain/TwainConfigurationBuilder.cs

@@ -26,20 +26,20 @@ namespace NTwain
             _platform = Environment.OSVersion.Platform;
         }
 
-        /// <summary>
+        ///// <summary>
-        /// Specifies which DSM to use. 
+        ///// Specifies which DSM to use. 
-        /// </summary>
+        ///// </summary>
-        /// <param name="legacyDsm"></param>
+        ///// <param name="legacyDsm"></param>
-        /// <returns></returns>
+        ///// <returns></returns>
-        public TwainConfigurationBuilder UseDsm(bool legacyDsm = false)
+        //public TwainConfigurationBuilder UseDsm(bool legacyDsm = false)
-        {
+        //{
-            if (legacyDsm)
+        //    if (legacyDsm)
-            {
+        //    {
-                if (_64bit) throw new InvalidOperationException("Cannot use legacy DSM under 64bit.");
+        //        if (_64bit) throw new InvalidOperationException("Cannot use legacy DSM under 64bit.");
-            }
+        //    }
-            _legacy = legacyDsm;
+        //    _legacy = legacyDsm;
-            return this;
+        //    return this;
-        }
+        //}
 
         /// <summary>
         /// Specifies what kind of data the app can to handle from TWAIN devices.
@@ -101,7 +101,7 @@ namespace NTwain
         /// <returns></returns>
         public TwainConfig Build()
         {
-            ITW_IDENTITY app = null;
+            var config = new TwainConfig();
 
             // todo: change id based on platform
             switch (_platform)
@@ -110,7 +110,7 @@ namespace NTwain
                 case PlatformID.Unix:
                 case PlatformID.MacOSX:
                 default:
-                    app = new TW_IDENTITY
+                    config.AppWin32 = new TW_IDENTITY
                     {
                         DataFunctionalities = DataFunctionalities.App2,
                         DataGroup = DataGroups.Control | _dg,
@@ -130,12 +130,7 @@ namespace NTwain
                     };
                     break;
             }
-
+            return config;
-            return new TwainConfig
-            {
-                PreferLegacyDsm = _legacy,
-                App = app
-            };
         }
     }
 }

src/NTwain/TwainSession.Disposable.cs

@@ -0,0 +1,52 @@
+using NTwain.Data;
+using NTwain.Triplets;
+using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Linq;
+using System.Text;
+
+namespace NTwain
+{
+    partial class TwainSession : IDisposable
+    {
+        private bool disposedValue = false; // To detect redundant calls
+
+        /// <summary>
+        /// Handles actual disposal logic.
+        /// </summary>
+        /// <param name="disposing"></param>
+        protected virtual void Dispose(bool disposing)
+        {
+            if (!disposedValue)
+            {
+                if (disposing)
+                {
+                    StepDown(TwainState.DsmLoaded);
+                    // TODO: dispose managed state (managed objects).
+                }
+
+                // TODO: free unmanaged resources (unmanaged objects) and override a finalizer below.
+                // TODO: set large fields to null.
+
+                disposedValue = true;
+            }
+        }
+
+        // TODO: override a finalizer only if Dispose(bool disposing) above has code to free unmanaged resources.
+        // ~TwainSession() {
+        //   // Do not change this code. Put cleanup code in Dispose(bool disposing) above.
+        //   Dispose(false);
+        // }
+
+        /// <summary>
+        /// Closes any open TWAIN objects.
+        /// </summary>
+        public void Dispose()
+        {
+            Dispose(true);
+            // TODO: uncomment the following line if the finalizer is overridden above.
+            // GC.SuppressFinalize(this);
+        }
+    }
+}

src/NTwain/TwainSession.Props.cs

@@ -0,0 +1,66 @@
+using NTwain.Data;
+using NTwain.Triplets;
+using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Linq;
+using System.Text;
+
+namespace NTwain
+{
+    partial class TwainSession : INotifyPropertyChanged
+    {
+        private TwainState _state;
+        /// <summary>
+        /// Gets the logical state of the session.
+        /// </summary>
+        public TwainState State
+        {
+            get { return _state; }
+            internal set
+            {
+                _state = value;
+                RaisePropertyChanged(nameof(State));
+            }
+        }
+
+        DGControl dgControl;
+        /// <summary>
+        /// Gets the triplet operations defined for control data group.
+        /// </summary>
+        public DGControl DGControl => dgControl ?? (dgControl = new DGControl(this));
+
+        DGImage dgImage;
+        /// <summary>
+        /// Gets the triplet operations defined for image data group.
+        /// </summary>
+        public DGImage DGImage => dgImage ?? (dgImage = new DGImage(this));
+
+        DGAudio dgAudio;
+        /// <summary>
+        /// Gets the triplet operations defined for audio data group.
+        /// </summary>
+        public DGAudio DGAudio => dgAudio ?? (dgAudio = new DGAudio(this));
+
+        /// <summary>
+        /// Gets/sets the direct triplet operation entry for custom values.
+        /// </summary>
+        public DGCustom DGCustom { get; set; }
+
+
+        /// <summary>
+        /// Occurs when a property value changes.
+        /// </summary>
+        public event PropertyChangedEventHandler PropertyChanged;
+
+        /// <summary>
+        /// Raises the <see cref="PropertyChanged"/> event.
+        /// </summary>
+        /// <param name="propertyName">Name of the property.</param>
+        protected void RaisePropertyChanged(string propertyName)
+        {
+            var handle = PropertyChanged;
+            handle?.Invoke(this, new PropertyChangedEventArgs(propertyName));
+        }
+    }
+}

src/NTwain/TwainSession.cs

@@ -1,4 +1,5 @@
 using NTwain.Data;
+using NTwain.Triplets;
 using System;
 using System.Collections.Generic;
 using System.ComponentModel;
@@ -7,87 +8,36 @@ using System.Text;
 
 namespace NTwain
 {
-    public class TwainSession : INotifyPropertyChanged, IDisposable
+    public partial class TwainSession
     {
-        private TwainConfig _config;
+        internal TwainConfig Config;
+        private IntPtr _hWnd;
+
         public TwainSession(TwainConfig config)
         {
-            _config = config;
+            Config = config;
-            var rc = Open();
+        }
-            if (rc != ReturnCode.Success)
+
+        public ReturnCode Open(ref IntPtr hWnd)
+        {
+            _hWnd = hWnd;
+            return DGControl.Parent.OpenDSM(ref hWnd);
+        }
+
+        public ReturnCode StepDown(TwainState targetState)
+        {
+            var rc = ReturnCode.Failure;
+            while (State > targetState)
             {
-
+                switch (State)
-            }
-        }
-
-        private TwainState _state;
-        /// <summary>
-        /// Gets the logical state of the session.
-        /// </summary>
-        public TwainState State
-        {
-            get { return _state; }
-            internal set
-            {
-                _state = value;
-                RaisePropertyChanged(nameof(State));
-            }
-        }
-
-        public event PropertyChangedEventHandler PropertyChanged;
-        void RaisePropertyChanged(string property)
-        {
-            var handle = PropertyChanged;
-            handle?.Invoke(this, new PropertyChangedEventArgs(property));
-        }
-
-        ReturnCode Open()
-        {
-            if (State < TwainState.DsmOpened)
-            {
-
-            }
-            throw new NotImplementedException();
-        }
-
-        ReturnCode StepDown(TwainState targetState)
-        {
-            throw new NotImplementedException();
-        }
-
-        #region IDisposable Support
-        private bool disposedValue = false; // To detect redundant calls
-
-        protected virtual void Dispose(bool disposing)
-        {
-            if (!disposedValue)
-            {
-                if (disposing)
                 {
-                    StepDown(TwainState.DsmLoaded);
+                    case TwainState.DsmOpened:
-                    // TODO: dispose managed state (managed objects).
+                        rc = DGControl.Parent.CloseDSM(ref _hWnd);
+                        if (rc != ReturnCode.Success) return rc;
+                        break;
                 }
-
-                // TODO: free unmanaged resources (unmanaged objects) and override a finalizer below.
-                // TODO: set large fields to null.
-
-                disposedValue = true;
             }
+            return rc;
         }
-
-        // TODO: override a finalizer only if Dispose(bool disposing) above has code to free unmanaged resources.
-        // ~TwainSession() {
-        //   // Do not change this code. Put cleanup code in Dispose(bool disposing) above.
-        //   Dispose(false);
-        // }
-
-        // This code added to correctly implement the disposable pattern.
-        public void Dispose()
-        {
-            Dispose(true);
-            // TODO: uncomment the following line if the finalizer is overridden above.
-            // GC.SuppressFinalize(this);
-        }
-        #endregion
     }
 }