Added pluggable log (#44)

samples/Sample.WPF/MainWindow.xaml.cs

@@ -30,18 +30,18 @@ namespace Sample.WPF
             {
                 _twainVM = this.DataContext as TwainVM;
 
-                Messenger.Default.Register<RefreshCommandsMessage>(this, m => m.HandleRefreshCommands());
+                Messenger.Default.Register<RefreshCommandsMessage>(this, m => m.HandleIt());
-                Messenger.Default.Register<DialogMessage>(this, msg =>
+                Messenger.Default.Register<MessageBoxMessage>(this, msg =>
                 {
                     if (Dispatcher.CheckAccess())
                     {
-                        this.HandleDialogMessageModern(msg);
+                        msg.HandleWithModern(this);
                     }
                     else
                     {
                         Dispatcher.BeginInvoke(new Action(() =>
                         {
-                            this.HandleDialogMessageModern(msg);
+                            msg.HandleWithModern(this);
                         }));
                     }
                 });

samples/Sample.WPF/Sample.WPF.csproj

@@ -44,8 +44,8 @@
   </PropertyGroup>
   <ItemGroup>
     <Reference Include="CommonWin32, Version=2.0.0.0, Culture=neutral, PublicKeyToken=a0a4edcfe233918d, processorArchitecture=MSIL">
-      <SpecificVersion>False</SpecificVersion>
+      <HintPath>..\..\packages\CommonWin32.2.0.5.6\lib\net35-Client\CommonWin32.dll</HintPath>
-      <HintPath>..\..\packages\CommonWin32.2.0.5.5\lib\net35-Client\CommonWin32.dll</HintPath>
+      <Private>True</Private>
     </Reference>
     <Reference Include="GalaSoft.MvvmLight, Version=5.1.1.35051, Culture=neutral, PublicKeyToken=0e453835af4ee6ce, processorArchitecture=MSIL">
       <HintPath>..\..\packages\MvvmLightLibs.5.1.1.0\lib\net40\GalaSoft.MvvmLight.dll</HintPath>
@@ -70,11 +70,12 @@
       <HintPath>..\..\packages\Microsoft.WindowsAPICodePack-Shell.1.1.0.0\lib\Microsoft.WindowsAPICodePack.ShellExtensions.dll</HintPath>
     </Reference>
     <Reference Include="ModernWPF, Version=1.0.0.0, Culture=neutral, PublicKeyToken=c99d0cfbea7491ef, processorArchitecture=MSIL">
-      <HintPath>..\..\packages\ModernWPF.1.2.10\lib\net40-Client\ModernWPF.dll</HintPath>
+      <HintPath>..\..\packages\ModernWPF.1.3.0\lib\net40-Client\ModernWPF.dll</HintPath>
       <Private>True</Private>
     </Reference>
-    <Reference Include="ModernWPF.Mvvm">
+    <Reference Include="ModernWPF.Mvvm, Version=0.7.0.0, Culture=neutral, processorArchitecture=MSIL">
-      <HintPath>..\..\packages\ModernWPF.Mvvm.0.7.0\lib\net40-Client\ModernWPF.Mvvm.dll</HintPath>
+      <HintPath>..\..\packages\ModernWPF.Mvvm.0.7.3\lib\net40-Client\ModernWPF.Mvvm.dll</HintPath>
+      <Private>True</Private>
     </Reference>
     <Reference Include="System" />
     <Reference Include="System.Data" />

samples/Sample.WPF/ViewModels/TwainVM.cs

@@ -225,7 +225,7 @@ namespace Sample.WPF
             {
                 if (e.Exception != null)
                 {
-                    Messenger.Default.Send(new DialogMessage(e.Exception.Message, null)
+                    Messenger.Default.Send(new MessageBoxMessage    (e.Exception.Message, null)
                     {
                         Caption = "Transfer Error Exception",
                         Icon = System.Windows.MessageBoxImage.Error,
@@ -234,7 +234,7 @@ namespace Sample.WPF
                 }
                 else
                 {
-                    Messenger.Default.Send(new DialogMessage(string.Format("Return Code: {0}\nCondition Code: {1}", e.ReturnCode, e.SourceStatus.ConditionCode), null)
+                    Messenger.Default.Send(new MessageBoxMessage(string.Format("Return Code: {0}\nCondition Code: {1}", e.ReturnCode, e.SourceStatus.ConditionCode), null)
                     {
                         Caption = "Transfer Error",
                         Icon = System.Windows.MessageBoxImage.Error,

samples/Sample.WPF/packages.config

@@ -1,10 +1,10 @@
 <?xml version="1.0" encoding="utf-8"?>
 <packages>
-  <package id="CommonServiceLocator" version="1.3" targetFramework="net40-Client" />
+  <package id="CommonServiceLocator" version="1.3" targetFramework="net4-client" userInstalled="true" />
-  <package id="CommonWin32" version="2.0.5.5" targetFramework="net40-Client" />
+  <package id="CommonWin32" version="2.0.5.6" targetFramework="net4-client" userInstalled="true" />
-  <package id="Microsoft.WindowsAPICodePack-Core" version="1.1.0.2" targetFramework="net40-Client" />
+  <package id="Microsoft.WindowsAPICodePack-Core" version="1.1.0.2" targetFramework="net4-client" userInstalled="true" />
-  <package id="Microsoft.WindowsAPICodePack-Shell" version="1.1.0.0" targetFramework="net40-Client" />
+  <package id="Microsoft.WindowsAPICodePack-Shell" version="1.1.0.0" targetFramework="net4-client" userInstalled="true" />
-  <package id="ModernWPF" version="1.2.10" targetFramework="net40-Client" />
+  <package id="ModernWPF" version="1.3.0" targetFramework="net4-client" userInstalled="true" />
-  <package id="ModernWPF.Mvvm" version="0.7.0" targetFramework="net40-Client" />
+  <package id="ModernWPF.Mvvm" version="0.7.3" targetFramework="net4-client" userInstalled="true" />
-  <package id="MvvmLightLibs" version="5.1.1.0" targetFramework="net40-Client" />
+  <package id="MvvmLightLibs" version="5.1.1.0" targetFramework="net4-client" userInstalled="true" />
 </packages>

samples/Sample.Winform/TestForm.cs

@@ -67,22 +67,22 @@ namespace Sample.Winform
             _twain = new TwainSession(appId);
             _twain.StateChanged += (s, e) =>
             {
-                Debug.WriteLine("State changed to " + _twain.State + " on thread " + Thread.CurrentThread.ManagedThreadId);
+                PlatformInfo.Current.Log.Info("State changed to " + _twain.State + " on thread " + Thread.CurrentThread.ManagedThreadId);
             };
             _twain.TransferError += (s, e) =>
             {
-                Debug.WriteLine("Got xfer error on thread " + Thread.CurrentThread.ManagedThreadId);
+                PlatformInfo.Current.Log.Info("Got xfer error on thread " + Thread.CurrentThread.ManagedThreadId);
             };
             _twain.DataTransferred += (s, e) =>
             {
-                Debug.WriteLine("Transferred data event on thread " + Thread.CurrentThread.ManagedThreadId);
+                PlatformInfo.Current.Log.Info("Transferred data event on thread " + Thread.CurrentThread.ManagedThreadId);
 
                 // example on getting ext image info
                 var infos = e.GetExtImageInfo(ExtendedImageInfo.Camera).Where(it => it.ReturnCode == ReturnCode.Success);
                 foreach (var it in infos)
                 {
                     var values = it.ReadValues();
-                    Debug.WriteLine(string.Format("{0} = {1}", it.InfoID, values.FirstOrDefault()));
+                    PlatformInfo.Current.Log.Info(string.Format("{0} = {1}", it.InfoID, values.FirstOrDefault()));
                     break;
                 }
 
@@ -115,7 +115,7 @@ namespace Sample.Winform
             };
             _twain.SourceDisabled += (s, e) =>
             {
-                Debug.WriteLine("Source disabled event on thread " + Thread.CurrentThread.ManagedThreadId);
+                PlatformInfo.Current.Log.Info("Source disabled event on thread " + Thread.CurrentThread.ManagedThreadId);
                 this.BeginInvoke(new Action(() =>
                 {
                     btnStopScan.Enabled = false;
@@ -126,13 +126,13 @@ namespace Sample.Winform
             };
             _twain.TransferReady += (s, e) =>
             {
-                Debug.WriteLine("Transferr ready event on thread " + Thread.CurrentThread.ManagedThreadId);
+                PlatformInfo.Current.Log.Info("Transferr ready event on thread " + Thread.CurrentThread.ManagedThreadId);
                 e.CancelAll = _stopScan;
             };
 
             // either set sync context and don't worry about threads during events,
             // or don't and use control.invoke during the events yourself
-            Debug.WriteLine("Setup thread = " + Thread.CurrentThread.ManagedThreadId);
+            PlatformInfo.Current.Log.Info("Setup thread = " + Thread.CurrentThread.ManagedThreadId);
             _twain.SynchronizationContext = SynchronizationContext.Current;
             if (_twain.State < 3)
             {

src/NTwain.Net35/NTwain.Net35.csproj

@@ -85,6 +85,9 @@
     <Compile Include="..\NTwain\IDataSource.cs">
       <Link>IDataSource.cs</Link>
     </Compile>
+    <Compile Include="..\NTwain\ILog.cs">
+      <Link>ILog.cs</Link>
+    </Compile>
     <Compile Include="..\NTwain\IMemoryManager.cs">
       <Link>IMemoryManager.cs</Link>
     </Compile>
@@ -112,6 +115,9 @@
     <Compile Include="..\NTwain\Internals\TentativeStateCommitable.cs">
       <Link>Internals\TentativeStateCommitable.cs</Link>
     </Compile>
+    <Compile Include="..\NTwain\Internals\TraceLog.cs">
+      <Link>Internals\TraceLog.cs</Link>
+    </Compile>
     <Compile Include="..\NTwain\Internals\TransferLogic.cs">
       <Link>Internals\TransferLogic.cs</Link>
     </Compile>

src/NTwain/DataSource.cs

@@ -36,7 +36,7 @@ namespace NTwain
             var rc = ReturnCode.Failure;
             _session.MessageLoopHook.Invoke(() =>
             {
-                Debug.WriteLine(string.Format(CultureInfo.InvariantCulture, "Thread {0}: OpenSource.", Thread.CurrentThread.ManagedThreadId));
+                PlatformInfo.Current.Log.Debug("Thread {0}: OpenSource.", Thread.CurrentThread.ManagedThreadId);
 
                 rc = _session.DGControl.Identity.OpenDS(this);
                 _session.UpdateCallback();
@@ -53,7 +53,7 @@ namespace NTwain
             var rc = ReturnCode.Failure;
             _session.MessageLoopHook.Invoke(() =>
             {
-                Debug.WriteLine(string.Format(CultureInfo.InvariantCulture, "Thread {0}: CloseSource.", Thread.CurrentThread.ManagedThreadId));
+                PlatformInfo.Current.Log.Debug("Thread {0}: CloseSource.", Thread.CurrentThread.ManagedThreadId);
 
                 rc = _session.DGControl.Identity.CloseDS();
                 //if (rc == ReturnCode.Success)

src/NTwain/ILog.cs

@@ -0,0 +1,83 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace NTwain
+{
+    /// <summary>
+    /// Simple log interface used by NTwain.
+    /// </summary>
+    public interface ILog
+    {
+        /// <summary>
+        /// Gets or sets a value indicating whether info messages will be logged.
+        /// </summary>
+        /// <value>
+        /// <c>true</c> to enable info logging.
+        /// </value>
+        bool IsInfoEnabled { get; set; }
+
+        /// <summary>
+        /// Gets or sets a value indicating whether debug messages will be logged.
+        /// </summary>
+        /// <value>
+        /// <c>true</c> to enable debug logging.
+        /// </value>
+        bool IsDebugEnabled { get; set; }
+
+        /// <summary>
+        /// Gets or sets a value indicating whether error messages will be logged.
+        /// </summary>
+        /// <value>
+        /// <c>true</c> to enable error logging.
+        /// </value>
+        bool IsErrorEnabled { get; set; }
+
+        /// <summary>
+        /// Logs info type message.
+        /// </summary>
+        /// <param name="message">The message.</param>
+        void Info(string message);
+
+        /// <summary>
+        /// Logs info type message.
+        /// </summary>
+        /// <param name="messageFormat">The message format.</param>
+        /// <param name="args">The arguments.</param>
+        void Info(string messageFormat, params object[] args);
+
+        /// <summary>
+        /// Logs debug type message.
+        /// </summary>
+        /// <param name="message">The message.</param>
+        void Debug(string message);
+        /// <summary>
+        /// Logs debug type message.
+        /// </summary>
+        /// <param name="messageFormat">The message format.</param>
+        /// <param name="args">The arguments.</param>
+        void Debug(string messageFormat, params object[] args);
+
+        /// <summary>
+        /// Logs error type message.
+        /// </summary>
+        /// <param name="message">The message.</param>
+        void Error(string message);
+        
+        /// <summary>
+        /// Logs error type message.
+        /// </summary>
+        /// <param name="message">The message.</param>
+        /// <param name="exception">The exception.</param>
+        void Error(string message, Exception exception);
+
+        /// <summary>
+        /// Logs error type message.
+        /// </summary>
+        /// <param name="messageFormat">The message format.</param>
+        /// <param name="exception">The exception.</param>
+        /// <param name="args">The arguments.</param>
+        void Error(string messageFormat, Exception exception, params object[] args);
+    }
+}

src/NTwain/IPlatformInfo.cs

@@ -86,5 +86,13 @@ namespace NTwain
         /// The memory manager.
         /// </value>
         IMemoryManager MemoryManager { get; }
+
+        /// <summary>
+        /// Gets or sets the log used by NTwain.
+        /// </summary>
+        /// <value>
+        /// The log.
+        /// </value>
+        ILog Log { get; set; }
     }
 }

src/NTwain/Internals/InternalMessageLoopHook.cs

@@ -34,7 +34,7 @@ namespace NTwain.Internals
                 {
                     var loopThread = new Thread(new ThreadStart(() =>
                     {
-                        Debug.WriteLine("NTwain message loop is starting.");
+                        PlatformInfo.Current.Log.Debug("NTwain internal message loop is starting.");
                         _dispatcher = Dispatcher.CurrentDispatcher;
                         if (!PlatformInfo.Current.IsOnMono)
                         {

src/NTwain/Internals/TraceLog.cs

@@ -0,0 +1,82 @@
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.Linq;
+using System.Text;
+
+namespace NTwain.Internals
+{
+    class TraceLog : ILog
+    {
+        public TraceLog()
+        {
+            IsInfoEnabled = true;
+            IsErrorEnabled = true;
+        }
+
+        public bool IsInfoEnabled { get; set; }
+
+        public bool IsDebugEnabled { get; set; }
+
+        public bool IsErrorEnabled { get; set; }
+
+
+        public void Info(string message)
+        {
+            if (IsInfoEnabled && message != null)
+            {
+                System.Diagnostics.Trace.WriteLine(message, "Info");
+            }
+        }
+
+        public void Info(string messageFormat, params object[] args)
+        {
+            Debug(string.Format(CultureInfo.CurrentCulture, messageFormat, args));
+        }
+
+        public void Debug(string message)
+        {
+            if (IsDebugEnabled && message != null)
+            {
+                System.Diagnostics.Trace.WriteLine(message, "Debug");
+            }
+        }
+
+        public void Debug(string messageFormat, params object[] args)
+        {
+            Debug(string.Format(CultureInfo.CurrentCulture, messageFormat, args));
+        }
+
+        public void Error(string message)
+        {
+            if (IsErrorEnabled && message != null)
+            {
+                System.Diagnostics.Trace.WriteLine(message, "Error");
+            }
+        }
+
+        public void Error(string message, Exception exception)
+        {
+            if (exception == null)
+            {
+                Error(message);
+            }
+            else
+            {
+                Error(message + Environment.NewLine + exception.ToString());
+            }
+        }
+
+        public void Error(string messageFormat, Exception exception, params object[] args)
+        {
+            if (exception == null)
+            {
+                Error(string.Format(CultureInfo.CurrentCulture, messageFormat, args));
+            }
+            else
+            {
+                Error(string.Format(CultureInfo.CurrentCulture, messageFormat, args) + Environment.NewLine + exception.ToString());
+            }
+        }
+    }
+}

src/NTwain/Internals/WindowsHook.cs

@@ -47,7 +47,6 @@ namespace NTwain.Internals
             }
             if (!handled)
             {
-                Debug.WriteLine("Hwnd=" + hwnd);
                 handled = true;
                 // unnecessary to do default wndproc?
                 return NativeMethods.DefWindowProc(hwnd, (uint)msg, wParam, lParam);

src/NTwain/NTwain.csproj

@@ -63,6 +63,8 @@
     <Compile Include="DeviceEventArgs.cs" />
     <Compile Include="GlobalSuppressions.cs" />
     <Compile Include="IDataSource.cs" />
+    <Compile Include="ILog.cs" />
+    <Compile Include="Internals\TraceLog.cs" />
     <Compile Include="Internals\Extensions.cs" />
     <Compile Include="DataTransferredEventArgs.cs" />
     <Compile Include="IMemoryManager.cs" />

src/NTwain/PlatformInfo.cs

@@ -32,7 +32,7 @@ namespace NTwain
             IsOnMono = Type.GetType("Mono.Runtime") != null;
             IsWindows = Environment.OSVersion.Platform == PlatformID.Win32NT;
             IsLinux = Environment.OSVersion.Platform == PlatformID.Unix;
-
+            _defaultLog = new TraceLog();
             if (IsWindows)
             {
                 _defaultMemManager = new WinMemoryManager();
@@ -84,7 +84,7 @@ namespace NTwain
                         ExpectedDsmPath = newDsmPath;
                         IsSupported = DsmExists = File.Exists(ExpectedDsmPath);
                         UseNewWinDSM = true;
-                        Debug.WriteLine("Using new dsm in windows.");
+                        Log.Debug("Using new dsm in windows.");
                     }
                     else
                     {
@@ -92,14 +92,14 @@ namespace NTwain
                         {
                             ExpectedDsmPath = newDsmPath;
                             UseNewWinDSM = IsSupported = DsmExists = true;
-                            Debug.WriteLine("Using new dsm in windows.");
+                            Log.Debug("Using new dsm in windows.");
                         }
                         else
                         {
                             ExpectedDsmPath = oldDsmPath;
                             IsSupported = DsmExists = File.Exists(ExpectedDsmPath);
                             UseNewWinDSM = false;
-                            Debug.WriteLine("Using old dsm in windows.");
+                            Log.Debug("Using old dsm in windows.");
                         }
                     }
                 }
@@ -186,13 +186,29 @@ namespace NTwain
         {
             get
             {
-                if (_specifiedMemManager == null) { return _defaultMemManager; }
+                return _specifiedMemManager ?? _defaultMemManager;
-                return _specifiedMemManager;
             }
             internal set
             {
                 _specifiedMemManager = value;
             }
         }
+
+
+        readonly ILog _defaultLog;
+        private ILog _log;
+
+        /// <summary>
+        /// Gets or sets the log used by NTwain.
+        /// </summary>
+        /// <value>
+        /// The log.
+        /// </value>
+        public ILog Log
+        {
+            get { return _log ?? _defaultLog; }
+            set { _log = value; }
+        }
+
     }
 }

src/NTwain/Properties/VersionInfo.cs

@@ -23,7 +23,7 @@ namespace NTwain
         /// <summary>
         /// The build release version number.
         /// </summary>
-        public const string Build = "3.3.4"; // change this for each nuget release
+        public const string Build = "3.3.5"; // change this for each nuget release
 
 
     }

src/NTwain/TwainSession.cs

@@ -62,7 +62,7 @@ namespace NTwain
         DataSource GetSourceInstance(ITwainSessionInternal session, TWIdentity sourceId)
         {
             DataSource source = null;
-            Debug.WriteLine("Source id = " + sourceId.Id);
+            PlatformInfo.Current.Log.Debug("Source id = {0}", sourceId.Id);
             var key = string.Format(CultureInfo.InvariantCulture, "{0}|{1}|{2}|{3}", sourceId.Id, sourceId.Manufacturer, sourceId.ProductFamily, sourceId.ProductName);
             if (_ownedSources.ContainsKey(key))
             {
@@ -230,7 +230,7 @@ namespace NTwain
             var rc = ReturnCode.Failure;
             _msgLoopHook.Invoke(() =>
             {
-                Debug.WriteLine(string.Format(CultureInfo.InvariantCulture, "Thread {0}: OpenManager.", Thread.CurrentThread.ManagedThreadId));
+                PlatformInfo.Current.Log.Debug("Thread {0}: OpenManager.", Thread.CurrentThread.ManagedThreadId);
 
                 rc = ((ITwainSessionInternal)this).DGControl.Parent.OpenDsm(_msgLoopHook.Handle);
                 if (rc == ReturnCode.Success)
@@ -243,7 +243,7 @@ namespace NTwain
                         if (rc == ReturnCode.Success)
                         {
                             PlatformInfo.InternalCurrent.MemoryManager = entry;
-                            Debug.WriteLine("Using TWAIN2 memory functions.");
+                            PlatformInfo.Current.Log.Debug("Using TWAIN2 memory functions.");
                         }
                         else
                         {
@@ -264,7 +264,7 @@ namespace NTwain
             var rc = ReturnCode.Failure;
             _msgLoopHook.Invoke(() =>
             {
-                Debug.WriteLine(string.Format(CultureInfo.InvariantCulture, "Thread {0}: CloseManager.", Thread.CurrentThread.ManagedThreadId));
+                PlatformInfo.Current.Log.Debug("Thread {0}: CloseManager.", Thread.CurrentThread.ManagedThreadId);
 
                 rc = ((ITwainSessionInternal)this).DGControl.Parent.CloseDsm(_msgLoopHook.Handle);
                 if (rc == ReturnCode.Success)
@@ -360,7 +360,7 @@ namespace NTwain
         /// <param name="targetState">State of the target.</param>
         public void ForceStepDown(int targetState)
         {
-            Debug.WriteLine(string.Format(CultureInfo.InvariantCulture, "Thread {0}: ForceStepDown.", Thread.CurrentThread.ManagedThreadId));
+            PlatformInfo.Current.Log.Debug("Thread {0}: ForceStepDown.", Thread.CurrentThread.ManagedThreadId);
 
             bool origFlag = EnforceState;
             EnforceState = false;
@@ -462,7 +462,7 @@ namespace NTwain
                 }
                 catch (Exception ex)
                 {
-                    Debug.WriteLine("PropertyChanged event error: " + ex.ToString());
+                    PlatformInfo.Current.Log.Error("PropertyChanged event error.", ex);
                 }
             }
             else
@@ -476,7 +476,7 @@ namespace NTwain
                     }
                     catch (Exception ex)
                     {
-                        Debug.WriteLine("PropertyChanged event error: " + ex.ToString());
+                        PlatformInfo.Current.Log.Error("PropertyChanged event error.", ex);
                     }
                 }, null);
             }
@@ -533,7 +533,7 @@ namespace NTwain
                 }
                 catch (Exception ex)
                 {
-                    Debug.WriteLine(handler.Method.Name + " event error: " + ex.ToString());
+                    PlatformInfo.Current.Log.Error("{0} event error.", ex, handler.Method.Name);
                 }
             }
             else
@@ -547,7 +547,7 @@ namespace NTwain
                     }
                     catch (Exception ex)
                     {
-                        Debug.WriteLine(handler.Method.Name + " event error: " + ex.ToString());
+                        PlatformInfo.Current.Log.Error("{0} event error.", ex, handler.Method.Name);
                     }
                 }, null);
             }
@@ -566,7 +566,7 @@ namespace NTwain
             var syncer = SynchronizationContext;
             if (syncer == null)
             {
-                Debug.WriteLine(string.Format(CultureInfo.InvariantCulture, "Trying to raise event {0} on thread {1} without sync.", e.GetType().Name, Thread.CurrentThread.ManagedThreadId));
+                PlatformInfo.Current.Log.Debug("Trying to raise event {0} on thread {1} without sync.", e.GetType().Name, Thread.CurrentThread.ManagedThreadId);
 
                 try
                 {
@@ -575,12 +575,12 @@ namespace NTwain
                 }
                 catch (Exception ex)
                 {
-                    Debug.WriteLine(handler.Method.Name + " event error: " + ex.ToString());
+                    PlatformInfo.Current.Log.Error("{0} event error.", ex, handler.Method.Name);
                 }
             }
             else
             {
-                Debug.WriteLine(string.Format(CultureInfo.InvariantCulture, "Trying to raise event {0} on thread {1} with sync.", e.GetType().Name, Thread.CurrentThread.ManagedThreadId));
+                PlatformInfo.Current.Log.Debug("Trying to raise event {0} on thread {1} with sync.", e.GetType().Name, Thread.CurrentThread.ManagedThreadId);
                 // on some consumer desktop scanner with poor drivers this can frequently hang. there's nothing I can do here.
                 syncer.Send(o =>
                 {
@@ -591,7 +591,7 @@ namespace NTwain
                     }
                     catch (Exception ex)
                     {
-                        Debug.WriteLine(handler.Method.Name + " event error: " + ex.ToString());
+                        PlatformInfo.Current.Log.Error("{0} event error.", ex, handler.Method.Name);
                     }
                 }, null);
             }

src/NTwain/TwainSessionInternal.cs

@@ -45,7 +45,7 @@ namespace NTwain
 
                     if (rc == ReturnCode.Success)
                     {
-                        Debug.WriteLine("Registered callback2 OK.");
+                        PlatformInfo.Current.Log.Debug("Registered callback2 OK.");
                         _callbackObj = cb;
                     }
                 }
@@ -59,7 +59,7 @@ namespace NTwain
 
                     if (rc == ReturnCode.Success)
                     {
-                        Debug.WriteLine("Registered callback OK.");
+                        PlatformInfo.Current.Log.Debug("Registered callback OK.");
                         _callbackObj = cb;
                     }
                 }
@@ -159,7 +159,7 @@ namespace NTwain
 
             _msgLoopHook.Invoke(() =>
             {
-                Debug.WriteLine(string.Format(CultureInfo.InvariantCulture, "Thread {0}: EnableSource with {1}.", Thread.CurrentThread.ManagedThreadId, mode));
+                PlatformInfo.Current.Log.Debug("Thread {0}: EnableSource with {1}.", Thread.CurrentThread.ManagedThreadId, mode);
 
 
                 _twui = new TWUserInterface();
@@ -190,7 +190,7 @@ namespace NTwain
                 {
                     _msgLoopHook.Invoke(() =>
                     {
-                        Debug.WriteLine(string.Format(CultureInfo.InvariantCulture, "Thread {0}: DisableSource.", Thread.CurrentThread.ManagedThreadId));
+                        PlatformInfo.Current.Log.Debug("Thread {0}: DisableSource.", Thread.CurrentThread.ManagedThreadId);
 
                         rc = ((ITwainSessionInternal)this).DGControl.UserInterface.DisableDS(_twui);
                         if (rc == ReturnCode.Success)
@@ -242,7 +242,7 @@ namespace NTwain
                     evt.pEvent = msgPtr;
                     if (handled = (((ITwainSessionInternal)this).DGControl.Event.ProcessEvent(evt) == ReturnCode.DSEvent))
                     {
-                        Debug.WriteLine(string.Format(CultureInfo.InvariantCulture, "Thread {0}: HandleWndProcMessage at state {1} with MSG={2}.", Thread.CurrentThread.ManagedThreadId, State, evt.TWMessage));
+                        PlatformInfo.Current.Log.Debug("Thread {0}: HandleWndProcMessage at state {1} with MSG={2}.", Thread.CurrentThread.ManagedThreadId, State, evt.TWMessage);
 
                         HandleSourceMsg(evt.TWMessage);
                     }
@@ -264,7 +264,7 @@ namespace NTwain
         {
             if (origin != null && CurrentSource != null && origin.Id == CurrentSource.Identity.Id && _state >= 5)
             {
-                Debug.WriteLine(string.Format(CultureInfo.InvariantCulture, "Thread {0}: CallbackHandler at state {1} with MSG={2}.", Thread.CurrentThread.ManagedThreadId, State, msg));
+                PlatformInfo.Current.Log.Debug("Thread {0}: CallbackHandler at state {1} with MSG={2}.", Thread.CurrentThread.ManagedThreadId, State, msg);
                 // spec says we must handle this on the thread that enabled the DS.
                 // by using the internal dispatcher this will be the case.
 
@@ -282,6 +282,7 @@ namespace NTwain
         // final method that handles msg from the source, whether it's from wndproc or callbacks
         void HandleSourceMsg(Message msg)
         {
+            PlatformInfo.Current.Log.Debug("Got TWAIN msg " + msg);
             switch (msg)
             {
                 case Message.XferReady:
@@ -301,7 +302,6 @@ namespace NTwain
                     break;
                 case Message.CloseDSReq:
                 case Message.CloseDSOK:
-                    Debug.WriteLine("Got msg " + msg);
                     // even though it says closeDS it's really disable.
                     // dsok is sent if source is enabled with uionly