Renamed datatransferred event.

src/NTwain/TransferredEventArgs.cs

@@ -6,27 +6,30 @@ namespace NTwain
   // TODO: maybe a 2-level "dispose" with end of event being 1
   // and manual dispose 2 for perf if this is not good enough.
 
-  public class DataTransferredEventArgs : EventArgs
+  public class TransferredEventArgs : EventArgs
   {
-    public DataTransferredEventArgs(TW_AUDIOINFO info, TW_SETUPFILEXFER fileInfo)
+    public TransferredEventArgs(TW_AUDIOINFO info, TW_SETUPFILEXFER fileInfo)
     {
       AudioInfo = info;
       FileInfo = fileInfo;
     }
-    public DataTransferredEventArgs(TW_AUDIOINFO info, BufferedData data)
+    public TransferredEventArgs(TW_AUDIOINFO info, BufferedData data)
     {
       AudioInfo = info;
       _data = data;
     }
 
-    public DataTransferredEventArgs(TW_IMAGEINFO info, TW_SETUPFILEXFER? fileInfo, BufferedData data)
+    public TransferredEventArgs(TwainAppSession twain, TW_IMAGEINFO info, TW_SETUPFILEXFER? fileInfo, BufferedData data)
     {
       ImageInfo = info;
       FileInfo = fileInfo;
       IsImage = true;
       _data = data;
+      _twain = twain;
     }
 
+    TwainAppSession? _twain;
+
     /// <summary>
     /// Whether transferred data is an image or audio.
     /// </summary>
@@ -57,5 +60,18 @@ namespace NTwain
     /// </summary>
     public TW_AUDIOINFO AudioInfo { get; }
 
+    /// <summary>
+    /// Gets the ext image info. Use any utility methods on it 
+    /// to read the data. Remember to call <see cref="TW_EXTIMAGEINFO.Free(IMemoryManager)"/>
+    /// when done.
+    /// </summary>
+    /// <param name="container">Container to query. Can be created with <see cref="TW_EXTIMAGEINFO.CreateRequest(TWEI[])"/></param>
+    /// <returns></returns>
+    public STS GetExtendedImageInfo(ref TW_EXTIMAGEINFO container)
+    {
+      if (_twain == null) return default;
+      return _twain.GetExtendedImageInfo(ref container);
+    }
+
   }
 }

src/NTwain/TwainAppSession.PropEvents.cs

@@ -15,10 +15,6 @@ namespace NTwain
     public TW_IDENTITY_LEGACY AppIdentity
     {
       get => _appIdentity;
-      internal set
-      {
-        _appIdentity = value;
-      }
     }
     TW_IDENTITY_LEGACY _appIdentity;
 
@@ -28,7 +24,7 @@ namespace NTwain
     public TW_IDENTITY_LEGACY CurrentSource
     {
       get => _currentDS;
-      internal set
+      protected set
       {
         _currentDS = value;
         try
@@ -56,16 +52,22 @@ namespace NTwain
     public STATE State
     {
       get => _state;
-      internal set
+      protected set
       {
         if (_state != value)
         {
           _state = value;
+          if (StateChanged != null)
+          {
+            _uiThreadMarshaller.Invoke(() =>
+            {
           try
           {
-            StateChanged?.Invoke(this, value); // TODO: should care about thread
+                StateChanged.Invoke(this, value);
           }
           catch { }
+            });
+          }
         }
       }
     }
@@ -126,7 +128,6 @@ namespace NTwain
 
     /// <summary>
     /// Fires when <see cref="State"/> changes. 
-    /// This is not guaranteed to be raised on the UI thread.
     /// </summary>
     public event TwainEventDelegate<STATE>? StateChanged;
 
@@ -163,7 +164,8 @@ namespace NTwain
 
     /// <summary>
     /// Fires when transferred data is available for app to use.
+    /// This is NOT raised on the UI thread for reasons.
     /// </summary>
-    public event TwainEventDelegate<DataTransferredEventArgs>? DataTransferred;
+    public event TwainEventDelegate<TransferredEventArgs>? Transferred;
   }
 }

src/NTwain/TwainAppSession.Xfers.cs

@@ -67,14 +67,17 @@ namespace NTwain
         do
         {
           var readyArgs = new TransferReadyEventArgs(pending.Count, (TWEJ)pending.EOJ);
+          if (TransferReady != null)
+          {
           _uiThreadMarshaller.Invoke(() =>
           {
             try
             {
-              TransferReady?.Invoke(this, readyArgs);
+                TransferReady.Invoke(this, readyArgs);
             }
             catch { } // don't let consumer kill the loop if they have exception
           });
+          }
 
           if (readyArgs.Cancel == CancelType.EndNow || _closeDsRequested)
           {
@@ -108,7 +111,7 @@ namespace NTwain
             try
             {
               if (readyArgs.Cancel != CancelType.SkipCurrent &&
-                DataTransferred != null)
+                Transferred != null)
               {
                 // transfer normally and only if someone's listening
                 // to DataTransferred event
@@ -146,13 +149,19 @@ namespace NTwain
             }
             catch (Exception ex)
             {
+              if (TransferError != null)
+              {
+                _uiThreadMarshaller.Invoke(() =>
+                {
               try
               {
                 TransferError?.Invoke(this, new TransferErrorEventArgs(ex));
               }
               catch { }
+                });
             }
           }
+          }
         } while (sts.RC == TWRC.SUCCESS && pending.Count != 0);
       }
 
@@ -229,8 +238,8 @@ namespace NTwain
         try
         {
           DGAudio.AudioInfo.Get(ref _appIdentity, ref _currentDS, out TW_AUDIOINFO info);
-          var args = new DataTransferredEventArgs(info, fileSetup);
+          var args = new TransferredEventArgs(info, fileSetup);
-          DataTransferred?.Invoke(this, args);
+          Transferred?.Invoke(this, args);
         }
         catch { }
 ;
@@ -263,8 +272,8 @@ namespace NTwain
             try
             {
               DGAudio.AudioInfo.Get(ref _appIdentity, ref _currentDS, out TW_AUDIOINFO info);
-              var args = new DataTransferredEventArgs(info, data);
+              var args = new TransferredEventArgs(info, data);
-              DataTransferred?.Invoke(this, args);
+              Transferred?.Invoke(this, args);
             }
             catch { }
             finally
@@ -429,8 +438,8 @@ namespace NTwain
         {
           DGImage.ImageInfo.Get(ref _appIdentity, ref _currentDS, out TW_IMAGEINFO info);
           // ToArray bypasses the XferMemPool but I guess this will have to do for now
-          var args = new DataTransferredEventArgs(info, fileSetup, new BufferedData { Buffer = outStream.ToArray(), Length = (int)outStream.Length });
+          var args = new TransferredEventArgs(this, info, fileSetup, new BufferedData { Buffer = outStream.ToArray(), Length = (int)outStream.Length });
-          DataTransferred?.Invoke(this, args);
+          Transferred?.Invoke(this, args);
         }
         catch { }
 
@@ -457,8 +466,8 @@ namespace NTwain
         try
         {
           DGImage.ImageInfo.Get(ref _appIdentity, ref _currentDS, out TW_IMAGEINFO info);
-          var args = new DataTransferredEventArgs(info, fileSetup, default);
+          var args = new TransferredEventArgs(this, info, fileSetup, default);
-          DataTransferred?.Invoke(this, args);
+          Transferred?.Invoke(this, args);
         }
         catch { }
 
@@ -503,8 +512,8 @@ namespace NTwain
             try
             {
               DGImage.ImageInfo.Get(ref _appIdentity, ref _currentDS, out TW_IMAGEINFO info);
-              var args = new DataTransferredEventArgs(info, null, data);
+              var args = new TransferredEventArgs(this, info, null, data);
-              DataTransferred?.Invoke(this, args);
+              Transferred?.Invoke(this, args);
             }
             catch { }
             finally

src/NTwain/TwainAppSession.cs

@@ -133,23 +133,23 @@ namespace NTwain
             });
             break;
           case MSG.DEVICEEVENT:
-            if (DGControl.DeviceEvent.Get(ref _appIdentity, ref _currentDS, out TW_DEVICEEVENT de) == TWRC.SUCCESS)
+            if (DeviceEvent != null && DGControl.DeviceEvent.Get(ref _appIdentity, ref _currentDS, out TW_DEVICEEVENT de) == TWRC.SUCCESS)
             {
               _uiThreadMarshaller.BeginInvoke(() =>
               {
                 try
                 {
-                  DeviceEvent?.Invoke(this, de);
+                  DeviceEvent.Invoke(this, de);
                 }
                 catch { }
               });
             }
             break;
           case MSG.XFERREADY:
-            _uiThreadMarshaller.Invoke(() =>
+            //_uiThreadMarshaller.Invoke(() =>
-            {
+            //{
               State = STATE.S6;
-            });
+            //});
             EnterTransferRoutine();
             break;
         }