From bd3d70c9912066c7e877965d0aa38149c0c2c209 Mon Sep 17 00:00:00 2001
From: Eugene Wang <yinchun.wang@gmail.com>
Date: Thu, 15 Nov 2018 18:14:26 -0500
Subject: [PATCH] Added GetStatus() call.

---
 samples/NetCoreConsole/NetCoreConsole.csproj |  1 +
 samples/NetFXConsole/NetFXConsole.csproj     |  2 ++
 src/NTwain/DataSource.cs                     | 11 ++++++++++
 src/NTwain/NTwain.csproj                     |  1 +
 src/NTwain/Triplets/DGControl.Status.cs      | 22 ++++++++++++++++++++
 src/NTwain/Triplets/DGControl.cs             |  3 +++
 src/NTwain/TwainSession.cs                   | 17 +++++++++++++--
 7 files changed, 55 insertions(+), 2 deletions(-)
 create mode 100644 src/NTwain/Triplets/DGControl.Status.cs

diff --git a/samples/NetCoreConsole/NetCoreConsole.csproj b/samples/NetCoreConsole/NetCoreConsole.csproj
index e6186c2..8eeaeef 100644
--- a/samples/NetCoreConsole/NetCoreConsole.csproj
+++ b/samples/NetCoreConsole/NetCoreConsole.csproj
@@ -4,6 +4,7 @@
     <OutputType>Exe</OutputType>
     <TargetFramework>netcoreapp2.1</TargetFramework>
     <RootNamespace>ConsoleApp</RootNamespace>
+    <LangVersion>7.1</LangVersion>
   </PropertyGroup>
 
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|AnyCPU'">
diff --git a/samples/NetFXConsole/NetFXConsole.csproj b/samples/NetFXConsole/NetFXConsole.csproj
index 7b07811..8daac8d 100644
--- a/samples/NetFXConsole/NetFXConsole.csproj
+++ b/samples/NetFXConsole/NetFXConsole.csproj
@@ -21,6 +21,7 @@
     <DefineConstants>DEBUG;TRACE</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
+    <LangVersion>7.1</LangVersion>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
     <PlatformTarget>AnyCPU</PlatformTarget>
@@ -30,6 +31,7 @@
     <DefineConstants>TRACE</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
+    <LangVersion>7.1</LangVersion>
   </PropertyGroup>
   <ItemGroup>
     <Reference Include="System" />
diff --git a/src/NTwain/DataSource.cs b/src/NTwain/DataSource.cs
index afd446c..388a13a 100644
--- a/src/NTwain/DataSource.cs
+++ b/src/NTwain/DataSource.cs
@@ -35,6 +35,17 @@ namespace NTwain
         public ReturnCode Close() => Session.DGControl.Identity.CloseDS(Identity);
 
 
+        /// <summary>
+        /// Gets the source status. Useful after getting a non-success return code.
+        /// </summary>
+        /// <returns></returns>
+        public TW_STATUS GetStatus()
+        {
+            TW_STATUS stat = default;
+            var rc = Session.DGControl.Status.GetSourceStatus(ref stat);
+            return stat;
+        }
+
 
         /// <summary>
         /// Returns a <see cref="System.String"/> that represents this instance.
diff --git a/src/NTwain/NTwain.csproj b/src/NTwain/NTwain.csproj
index dd9733c..ee0973b 100644
--- a/src/NTwain/NTwain.csproj
+++ b/src/NTwain/NTwain.csproj
@@ -19,6 +19,7 @@
     <AssemblyVersion>4.0.0.0</AssemblyVersion>
     <FileVersion>4.0.0.0</FileVersion>
     <Version>4.0.0</Version>
+    <LangVersion>7.1</LangVersion>
   </PropertyGroup>
 
   <ItemGroup>
diff --git a/src/NTwain/Triplets/DGControl.Status.cs b/src/NTwain/Triplets/DGControl.Status.cs
new file mode 100644
index 0000000..c4b8163
--- /dev/null
+++ b/src/NTwain/Triplets/DGControl.Status.cs
@@ -0,0 +1,22 @@
+using NTwain.Data;
+using NTwain.Internals;
+
+namespace NTwain.Triplets
+{
+    sealed class Status : BaseTriplet
+    {
+        internal Status(TwainSession session) : base(session) { }
+
+        public ReturnCode GetManagerStatus(ref TW_STATUS status)
+        {
+            return NativeMethods.DsmWin32(Session.Config.AppWin32, null,
+                DataGroups.Control, DataArgumentType.Status, Message.Get, ref status);
+        }
+
+        public ReturnCode GetSourceStatus(ref TW_STATUS status)
+        {
+            return NativeMethods.DsmWin32(Session.Config.AppWin32, Session.CurrentSource.Identity,
+                DataGroups.Control, DataArgumentType.Status, Message.Get, ref status);
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/NTwain/Triplets/DGControl.cs b/src/NTwain/Triplets/DGControl.cs
index f2f6dc8..6e37c8b 100644
--- a/src/NTwain/Triplets/DGControl.cs
+++ b/src/NTwain/Triplets/DGControl.cs
@@ -27,5 +27,8 @@ namespace NTwain.Triplets
 
         Callback2 _callback2;
         internal Callback2 Callback2 => _callback2 ?? (_callback2 = new Callback2(Session));
+
+        Status _status;
+        internal Status Status => _status ?? (_status = new Status(Session));
     }
 }
diff --git a/src/NTwain/TwainSession.cs b/src/NTwain/TwainSession.cs
index 63e36bb..3cd1594 100644
--- a/src/NTwain/TwainSession.cs
+++ b/src/NTwain/TwainSession.cs
@@ -82,6 +82,17 @@ namespace NTwain
             return rc;
         }
 
+        /// <summary>
+        /// Gets the manager status. Useful after getting a non-success return code.
+        /// </summary>
+        /// <returns></returns>
+        public TW_STATUS GetStatus()
+        {
+            TW_STATUS stat = default;
+            var rc = DGControl.Status.GetManagerStatus(ref stat);
+            return stat;
+        }
+
         internal void RegisterCallback()
         {
             var callbackPtr = Marshal.GetFunctionPointerForDelegate(_callbackDelegate);
@@ -92,7 +103,8 @@ namespace NTwain
             if (rc == ReturnCode.Success) Debug.WriteLine("Registed Callback2 success.");
             else
             {
-
+                var status = GetStatus();
+                Debug.WriteLine($"Register Callback2 failed with condition code: {status.ConditionCode}.");
             }
 
 
@@ -106,7 +118,8 @@ namespace NTwain
                 if (rc == ReturnCode.Success) Debug.WriteLine("Registed Callback success.");
                 else
                 {
-
+                    var status = GetStatus();
+                    Debug.WriteLine($"Register Callback failed with {status.ConditionCode}.");
                 }
             }
         }