little of changes about get device sources

src/TwainDotNet/DataSource.cs

@@ -146,6 +146,27 @@ public bool SupportsDuplex
             }
         }
 
+        public bool CheckDeviceOnline()
+        {
+            try
+            {
+                var sourceVersion = new Version(SourceId.ProtocolMajor, SourceId.ProtocolMinor);
+                var minVer = ProtocolVersions.GetMinimumVersion(Capabilities.DeviceOnline);
+                if (sourceVersion >= minVer)
+                {
+                    //var cap = new Capability(Capabilities.DeviceOnline, TwainType.Bool, _applicationId, SourceId);
+                    var cap = Capability.GetBoolCapability(Capabilities.DeviceOnline, _applicationId, SourceId);
+                    if (!cap)
+                        throw new TwainException($"{SourceId.ProductName} is offline.");
+                }
+                return true;
+            }
+            catch
+            {
+                return false;
+            }
+        }
+
         public void NegotiateColour(ScanSettings scanSettings)
         {
             try
@@ -301,6 +322,7 @@ public void NegotiateProgressIndicator(ScanSettings scanSettings)
         public bool Open(ScanSettings settings)
         {
             OpenSource();
+            CheckDeviceOnline();
 
             if (settings.AbortWhenNoPaperDetectable && !PaperDetectable)
                 throw new FeederEmptyException();
@@ -464,10 +486,9 @@ public static DataSource UserSelected(Identity applicationId, IWindowsMessageHoo
 
             return new DataSource(applicationId, defaultSourceId, messageHook);
         }
-
-        public static List<DataSource> GetAllSources(Identity applicationId, IWindowsMessageHook messageHook)
+        public static List<string> GetAllSourceNames(Identity applicationId)
         {
-            var sources = new List<DataSource>();
+            var sources = new List<string>();
             Identity id = new Identity();
 
             // Get the first source
@@ -489,11 +510,12 @@ public static List<DataSource> GetAllSources(Identity applicationId, IWindowsMes
             }
             else
             {
-                sources.Add(new DataSource(applicationId, id, messageHook));
+                sources.Add(id.ProductName);
             }
 
             while (true)
             {
+                id = new Identity();
                 // Get the next source
                 result = Twain32Native.DsmIdentity(
                     applicationId,
@@ -512,20 +534,62 @@ public static List<DataSource> GetAllSources(Identity applicationId, IWindowsMes
                     throw new TwainException("Error enumerating sources.", result);
                 }
 
-                sources.Add(new DataSource(applicationId, id, messageHook));
+                sources.Add(id.ProductName);
             }
 
             return sources;
         }
-
+         
         public static DataSource GetSource(string sourceProductName, Identity applicationId, IWindowsMessageHook messageHook)
         {
-            // A little slower than it could be, if enumerating unnecessary sources is slow. But less code duplication.
-            foreach (var source in GetAllSources(applicationId, messageHook))
+            Identity id = new Identity();
+
+            // Get the first source
+            var result = Twain32Native.DsmIdentity(
+                applicationId,
+                IntPtr.Zero,
+                DataGroup.Control,
+                DataArgumentType.Identity,
+                Message.GetFirst,
+                id);
+
+            if (result == TwainResult.EndOfList)
+            {
+                return null;
+            }
+            else if (result != TwainResult.Success)
+            {
+                throw new TwainException("Error getting first source.", result);
+            }
+            else if (id.ProductName == sourceProductName)
+            {
+                return new DataSource(applicationId, id, messageHook);
+            }
+
+            while (true)
             {
-                if (sourceProductName.Equals(source.SourceId.ProductName, StringComparison.InvariantCultureIgnoreCase))
+                id = new Identity();
+                // Get the next source
+                result = Twain32Native.DsmIdentity(
+                    applicationId,
+                    IntPtr.Zero,
+                    DataGroup.Control,
+                    DataArgumentType.Identity,
+                    Message.GetNext,
+                    id);
+
+                if (result == TwainResult.EndOfList)
+                {
+                    break;
+                }
+                else if (result != TwainResult.Success)
+                {
+                    throw new TwainException("Error enumerating sources.", result);
+                }
+
+                else if (id.ProductName == sourceProductName)
                 {
-                    return source;
+                    return new DataSource(applicationId, id, messageHook);
                 }
             }
 

src/TwainDotNet/DataSourceManager.cs

@@ -18,6 +18,7 @@ public class DataSourceManager : IDisposable
 
         IWindowsMessageHook _messageHook;
         Event _eventMessage;
+        private object _extTag = null;
 
         public Identity ApplicationId { get; private set; }
         public DataSource DataSource { get; private set; }
@@ -72,14 +73,15 @@ public DataSourceManager(Identity applicationId, IWindowsMessageHook messageHook
 
         public IWindowsMessageHook MessageHook { get { return _messageHook; } }
 
-        public void StartScan(ScanSettings settings)
-        {
+        public bool StartScan(ScanSettings settings, object extTag)
+        { 
             bool scanning = false;
-
             try
             {
+                _extTag = extTag;
                 _messageHook.UseFilter = true;
                 scanning = DataSource.Open(settings);
+                return scanning;
             }
             catch (TwainException e)
             {
@@ -235,7 +237,7 @@ protected void TransferPictures()
                     {
                         using (var renderer = new BitmapRenderer(hbitmap))
                         {
-                            TransferImageEventArgs args = new TransferImageEventArgs(renderer.RenderToBitmap(), pendingTransfer.Count != 0);
+                            TransferImageEventArgs args = new TransferImageEventArgs(renderer.RenderToBitmap(), pendingTransfer.Count, this._extTag);
                             TransferImage(this, args);
                             if (!args.ContinueScanning)
                                 break;
@@ -263,7 +265,7 @@ protected void CloseDsAndCompleteScanning(Exception exception)
             DataSource.Close();
             try
             {
-                ScanningComplete(this, new ScanningCompleteEventArgs(exception));
+                ScanningComplete(this, new ScanningCompleteEventArgs(exception,this._extTag));
             }
             catch
             {

src/TwainDotNet/ProtocolVersions.cs

@@ -0,0 +1,209 @@
+ 
+using System;
+using System.Collections.Generic;
+using TwainDotNet.TwainNative;
+
+namespace TwainDotNet
+{
+    /// <summary>
+    /// Contains the minimum TWAIN protocol version for various things.
+    /// </summary>
+    public static class ProtocolVersions
+    {
+        internal static readonly Version v10 = new Version(1, 0);
+        internal static readonly Version v11 = new Version(1, 1);
+        internal static readonly Version v15 = new Version(1, 5);
+        internal static readonly Version v16 = new Version(1, 6);
+        internal static readonly Version v17 = new Version(1, 7);
+        internal static readonly Version v18 = new Version(1, 8);
+        internal static readonly Version v19 = new Version(1, 9);
+        internal static readonly Version v20 = new Version(2, 0);
+        internal static readonly Version v21 = new Version(2, 1);
+        internal static readonly Version v22 = new Version(2, 2);
+        internal static readonly Version v23 = new Version(2, 3);
+
+
+        static readonly Dictionary<Capabilities, Version> __capMinVersions = new Dictionary<Capabilities, Version>
+        {
+            { Capabilities.AXferMech , v18 },
+            { Capabilities.Alarms, v18 },
+            { Capabilities.AlarmVolume, v18 },
+            { Capabilities.Author, v10 },
+            { Capabilities.AutoFeed, v10 },
+            { Capabilities.AutomaticCapture, v18 },
+            { Capabilities.AutomaticSenseMedium, v21 },
+            { Capabilities.AutoScan, v16 },
+            { Capabilities.BatteryMinutes, v18 },
+            { Capabilities.BatteryPercentage, v18 },
+            { Capabilities.CameraEnabled, v20 },
+            { Capabilities.CameraOrder, v20 },
+            { Capabilities.CameraPreviewUI, v18 },
+            { Capabilities.CameraSide, v19 },
+            { Capabilities.Caption, v10 },
+            { Capabilities.ClearBuffers, v18 },
+            { Capabilities.ClearPage, v10 },
+            { Capabilities.CustomDSData, v17 },
+            { Capabilities.CustomInterfaceGuid, v21 },
+            { Capabilities.DeviceEvent, v18 },
+            { Capabilities.DeviceOnline, v16 },
+            { Capabilities.DeviceTimeDate, v18 },
+            { Capabilities.DoubleFeedDetection, v22 },
+            { Capabilities.DoubleFeedDetectionLength, v22 },
+            { Capabilities.DoubleFeedDetectionResponse, v22 },
+            { Capabilities.DoubleFeedDetectionSensitivity, v22 },
+            { Capabilities.Duplex, v17 },
+            { Capabilities.DuplexEnabled, v17 },
+            { Capabilities.Enabledsuionly, v17 },
+            { Capabilities.Endorser, v17 },
+            { Capabilities.Extendedcaps, v10 },
+            { Capabilities.FeederAlignment, v18 },
+            { Capabilities.FeederEnabled, v10 },
+            { Capabilities.FeederLoaded, v10 },
+            { Capabilities.FeederOrder, v18 },
+            { Capabilities.Feederpocket, v20 },
+            { Capabilities.FeederPrep, v20},
+            { Capabilities.FeedPage, v10 },
+            { Capabilities.Indicators, v11 },
+            { Capabilities.IndicatorsMode, v22 },
+            { Capabilities.JobControl, v17 },
+            { Capabilities.Language, v18 },
+            { Capabilities.MaxBatchBuffers, v18 },
+            { Capabilities.MicrEnabled, v20 },
+            { Capabilities.PaperDetectable, v16 },
+            { Capabilities.PaperHandling, v22 },
+            { Capabilities.PowerSaveTime, v18 },
+            { Capabilities.PowerSupply, v18 },
+            { Capabilities.Printer, v18 },
+            { Capabilities.PrinterEnabled, v18 },
+            { Capabilities.PrinterCharRotation, v23 },
+            { Capabilities.PrinterFontStyle, v23 },
+            { Capabilities.PrinterIndex, v18 },
+            { Capabilities.PrinterIndexLeadChar, v23 },
+            { Capabilities.PrinterIndexMaxValue, v23 },
+            { Capabilities.PrinterIndexNumDigits, v23 },
+            { Capabilities.PrinterIndexStep, v23 },
+            { Capabilities.PrinterIndexTrigger, v23 },
+            { Capabilities.PrinterMode, v18 },
+            { Capabilities.PrinterString, v18 },
+            { Capabilities.PrinterStringPreview, v23 },
+            { Capabilities.PrinterSuffix, v18 },
+            { Capabilities.PrinterVerticalOffset, v22 },
+            { Capabilities.ReAcquireAllowed, v18 },
+            { Capabilities.RewindPage, v10 },
+            { Capabilities.Segmented, v19 },
+            { Capabilities.SerialNumber, v18 },
+            { Capabilities.SupportedCapabilities, v10 },
+            { Capabilities.SupportedCapsSegmentUnique, v22 },
+            { Capabilities.SupportedDATs, v22 },
+            { Capabilities.TimeBeforeFirstCapture, v18 },
+            { Capabilities.TimeBetweenCaptures, v18 },
+            { Capabilities.Timedate, v10 },
+            { Capabilities.ThumbnailsEnabled, v17 },
+            { Capabilities.UIControllable, v16 },
+            { Capabilities.XferCount, v10 },
+
+            { Capabilities.Autobright, v10 },
+            { Capabilities.AutoDiscardBlankPages, v20 },
+            { Capabilities.Automaticborderdetection, v18 },
+            { Capabilities.AutomaticColorEnabled, v21 },
+            { Capabilities.AutomaticColorNonColorPixelType, v18 },
+            { Capabilities.AutomaticCropUsesFrame, v21 },
+            { Capabilities.Automaticdeskew, v18 },
+            { Capabilities.AutomaticLengthDetection, v21 },
+            { Capabilities.Automaticrotate, v18 },
+            { Capabilities.Autosize, v20 },
+            { Capabilities.Barcodedetectionenabled, v18 },
+            { Capabilities.Barcodemaxretries, v18 },
+            { Capabilities.Barcodemaxsearchpriorities, v18 },
+            { Capabilities.Barcodesearchmode, v18 },
+            { Capabilities.Barcodesearchpriorities, v18 },
+            { Capabilities.Barcodetimeout, v18 },
+            { Capabilities.BitDepth, v10 },
+            { Capabilities.Bitdepthreduction, v15 },
+            { Capabilities.Bitorder, v10 },
+            { Capabilities.Bitordercodes, v10 },
+            { Capabilities.Brightness, v10 },
+            { Capabilities.Ccittkfactor, v10 },
+            { Capabilities.ColorManagementEnabled, v21 },
+            { Capabilities.ICompression, v10 },
+            { Capabilities.Contrast, v10 },
+            { Capabilities.CustHalftone, v10 },
+            { Capabilities.ExposureTime, v10 },
+            { Capabilities.Extimageinfo, v17 },
+            { Capabilities.Feedertype, v19 },
+            { Capabilities.FilmType, v22 },
+            { Capabilities.Filter, v10 },
+            { Capabilities.Flashused, v16 }, // maybe
+            { Capabilities.Flashused2, v18 },
+            { Capabilities.Fliprotation, v18 },
+            { Capabilities.Frames, v10 },
+            { Capabilities.Gamma, v10 },
+            { Capabilities.Halftones, v10 },
+            { Capabilities.Highlight, v10 },
+            { Capabilities.Iccprofile, v19 },
+            { Capabilities.Imagedataset, v17 },
+            { Capabilities.ImageFileFormat, v10 },
+            { Capabilities.Imagefilter, v18 },
+            { Capabilities.ImageMerge, v21 },
+            { Capabilities.ImageMergeHeightThreshold, v21 },
+            { Capabilities.Jpegpixeltype, v10 },
+            { Capabilities.Jpegquality, v19 },
+            { Capabilities.JpegSubsampling, v22 },
+            { Capabilities.LampState, v10 },
+            { Capabilities.Lightpath, v10 },
+            { Capabilities.LightSource, v10 },
+            { Capabilities.MaxFrames, v10 },
+            { Capabilities.Minimumheight, v17 },
+            { Capabilities.Minimumwidth, v17 },
+            { Capabilities.Mirror, v22 },
+            { Capabilities.Noisefilter, v18 },
+            { Capabilities.Orientation, v10 },
+            { Capabilities.Overscan, v18 },
+            { Capabilities.Patchcodedetectionenabled, v18 },
+            { Capabilities.Patchcodemaxretries, v18 },
+            { Capabilities.Patchcodemaxsearchpriorities, v18 },
+            { Capabilities.Patchcodesearchmode, v18 },
+            { Capabilities.Patchcodesearchpriorities, v18 },
+            { Capabilities.Patchcodetimeout, v18 },
+            { Capabilities.PhysicalHeight, v10 },
+            { Capabilities.PhysicalWidth, v10 },
+            { Capabilities.Pixelflavor, v10 },
+            { Capabilities.Pixelflavorcodes, v10 },
+            { Capabilities.IPixelType, v10 },
+            { Capabilities.Planarchunky, v10 },
+            { Capabilities.Rotation, v10 },
+            { Capabilities.Shadow, v10 },
+            { Capabilities.Supportedbarcodetypes, v18 },
+            { Capabilities.SupportedExtImageInfo, v21 },
+            { Capabilities.Supportedpatchcodetypes, v18 },
+            { Capabilities.Supportedsizes, v10 },
+            { Capabilities.Threshold, v10 },
+            { Capabilities.Tiles, v10 },
+            { Capabilities.Timefill, v10 },
+            { Capabilities.Undefinedimagesize, v16 },
+            { Capabilities.IUnits, v10 },
+            { Capabilities.IXferMech, v10 },
+            { Capabilities.XNativeResolution, v10 },
+            { Capabilities.XResolution, v10 },
+            { Capabilities.Xscaling, v10 },
+            { Capabilities.YNativeResolution, v10 },
+            { Capabilities.YResolution, v10 },
+            { Capabilities.Yscaling, v10 },
+            { Capabilities.Zoomfactor, v18 },
+        };
+
+        /// <summary>
+        /// Gets the minimum TWAIN protocol version for a capability.
+        /// </summary>
+        /// <param name="id">The capability type.</param>
+        /// <returns></returns>
+        public static Version GetMinimumVersion(Capabilities id)
+        {
+            if (__capMinVersions.ContainsKey(id))
+            {
+                return __capMinVersions[id];
+            }
+            return v10;
+        }
+    }
+}

src/TwainDotNet/ScanningCompleteEventArgs.cs

@@ -5,9 +5,11 @@ namespace TwainDotNet
     public class ScanningCompleteEventArgs : EventArgs
     {
         public Exception Exception { get; private set; }
+        public object ExtTag { private set; get; }
 
-        public ScanningCompleteEventArgs(Exception exception)
+        public ScanningCompleteEventArgs(Exception exception,object extTag)
         {
+            this.ExtTag = extTag;
             this.Exception = exception;
         }
     }