Trying to resurrect my old cap wrapper.

src/NTwain/Caps/CapReader.cs

@@ -0,0 +1,91 @@
+using NTwain.Data;
+using System;
+using System.Collections.Generic;
+
+namespace NTwain.Caps
+{
+  public class CapReader<TValue> where TValue : struct
+  {
+    readonly TwainAppSession _twain;
+
+    public CapReader(TwainAppSession twain, CAP cap)
+    {
+      _twain = twain;
+      Cap = cap;
+    }
+
+    public CAP Cap { get; }
+
+    public STS LastSTS { get; private set; }
+
+    TWQC? _qc;
+    public TWQC Supports
+    {
+      get
+      {
+        if (!_qc.HasValue) _qc = _twain.QueryCapSupport(Cap);
+        return _qc.Value;
+      }
+    }
+
+    public IList<TValue> Get()
+    {
+      LastSTS = _twain.GetCapValues(Cap, out IList<TValue> values);
+      if (LastSTS.IsSuccess)
+      {
+        return values;
+      };
+      return Array.Empty<TValue>();
+    }
+
+    public TValue GetCurrent()
+    {
+      LastSTS = _twain.GetCapCurrent(Cap, out TValue value);
+      if (LastSTS.IsSuccess)
+      {
+        return value;
+      };
+      return default;
+    }
+
+    public TValue GetDefault()
+    {
+      LastSTS = _twain.GetCapDefault(Cap, out TValue value);
+      if (LastSTS.IsSuccess)
+      {
+        return value;
+      };
+      return default;
+    }
+
+    public string? GetLabel()
+    {
+      LastSTS = _twain.GetCapLabel(Cap, out string? value);
+      if (LastSTS.IsSuccess)
+      {
+        return value;
+      };
+      return default;
+    }
+
+    public string? GetHelp()
+    {
+      LastSTS = _twain.GetCapHelp(Cap, out string? value);
+      if (LastSTS.IsSuccess)
+      {
+        return value;
+      };
+      return default;
+    }
+
+    public IList<string> GetLabelEnum()
+    {
+      LastSTS = _twain.GetCapLabelEnum(Cap, out IList<string> value);
+      if (LastSTS.IsSuccess)
+      {
+        return value;
+      };
+      return Array.Empty<string>();
+    }
+  }
+}

src/NTwain/Caps/CapWriter.cs

@@ -0,0 +1,16 @@
+using NTwain.Data;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace NTwain.Caps
+{
+  public class CapWriter<TValue> : CapReader<TValue> where TValue : struct
+  {
+    public CapWriter(TwainAppSession twain, CAP cap) : base(twain, cap)
+    {
+    }
+  }
+}

src/NTwain/Caps/KnownCaps.Audio.cs

@@ -0,0 +1,14 @@
+using NTwain.Data;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace NTwain.Caps
+{
+  partial class KnownCaps
+  {
+
+  }
+}

src/NTwain/Caps/KnownCaps.General.cs

@@ -0,0 +1,14 @@
+using NTwain.Data;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace NTwain.Caps
+{
+  partial class KnownCaps
+  {
+
+  }
+}

src/NTwain/Caps/KnownCaps.Image.cs

@@ -0,0 +1,14 @@
+using NTwain.Data;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace NTwain.Caps
+{
+  partial class KnownCaps
+  {
+
+  }
+}

src/NTwain/Caps/KnownCaps.cs

@@ -0,0 +1,23 @@
+using NTwain.Data;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace NTwain.Caps
+{
+  /// <summary>
+  /// Provides reader/writer wrapper of known <see cref="CAP"/>s.
+  /// </summary>
+  public partial class KnownCaps
+  {
+    private readonly TwainAppSession _twain;
+
+    public KnownCaps(TwainAppSession twain)
+    {
+      _twain = twain;
+    }
+
+  }
+}

src/NTwain/TwainAppSession.Caps.cs

@@ -1,5 +1,7 @@
-using NTwain.Data;
+using NTwain.Caps;
+using NTwain.Data;
 using NTwain.Triplets;
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Text;
@@ -10,20 +12,16 @@ namespace NTwain
 
   partial class TwainAppSession
   {
-    ///// <summary>
+    private KnownCaps? _knownCaps;
-    ///// Gets all the supported caps for the current source.
+
-    ///// </summary>
+    /// <summary>
-    ///// <returns></returns>
+    /// Access the known and pre-defined caps as properties.
-    //public IList<CAP> GetAllCaps()
+    /// </summary>
-    //{
+    public KnownCaps Caps
-    //  // just as a sample of how to read cap values
+    {
+      get { return _knownCaps ??= new KnownCaps(this); }
+    }
 
-    //  if (GetCapValues(CAP.CAP_SUPPORTEDCAPS, out TW_CAPABILITY value).RC == TWRC.SUCCESS)
-    //  {
-    //    return value.ReadArray<CAP>(this);
-    //  }
-    //  return Array.Empty<CAP>();
-    //}
 
     /// <summary>
     /// Gets a CAP's actual supported operations. 
@@ -251,9 +249,9 @@ namespace NTwain
     /// <param name="cap"></param>
     /// <param name="labels"></param>
     /// <returns></returns>
-    public STS GetCapLabelEnum(CAP cap, out IList<string>? labels)
+    public STS GetCapLabelEnum(CAP cap, out IList<string> labels)
     {
-      labels = null;
+      labels = Array.Empty<string>();
       var value = new TW_CAPABILITY(cap);
       var rc = DGControl.Capability.GetLabelEnum(ref _appIdentity, ref _currentDS, ref value);
       if (rc == TWRC.SUCCESS)