Add call to open DS in wrapper.

NTwain.sln

@@ -14,6 +14,10 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "common", "common", "{4CE0B9
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "NTwain", "NTwain\NTwain.csproj", "{B391C1B7-5647-4B7A-9079-81E835E633DD}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Net5Console", "samples\Net5Console\Net5Console.csproj", "{9F6C1B39-D0C9-4466-96A0-AB41C58762A9}"
+EndProject
+Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Samples", "Samples", "{707B4313-8EF8-4D0F-A95E-590783422187}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -24,10 +28,17 @@ Global
 		{B391C1B7-5647-4B7A-9079-81E835E633DD}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{B391C1B7-5647-4B7A-9079-81E835E633DD}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{B391C1B7-5647-4B7A-9079-81E835E633DD}.Release|Any CPU.Build.0 = Release|Any CPU
+		{9F6C1B39-D0C9-4466-96A0-AB41C58762A9}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{9F6C1B39-D0C9-4466-96A0-AB41C58762A9}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{9F6C1B39-D0C9-4466-96A0-AB41C58762A9}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{9F6C1B39-D0C9-4466-96A0-AB41C58762A9}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
 	EndGlobalSection
+	GlobalSection(NestedProjects) = preSolution
+		{9F6C1B39-D0C9-4466-96A0-AB41C58762A9} = {707B4313-8EF8-4D0F-A95E-590783422187}
+	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {7459323B-44F6-4E07-8574-E1B4B525086B}
 	EndGlobalSection

NTwain/Internal/TwainUtility.cs

@@ -1,13 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
-
-namespace NTwain.Internal
-{
-    static class TwainUtility
-    {
-
-    }
-}

NTwain/TwainSession.cs

@@ -55,6 +55,11 @@ namespace NTwain
             GC.SuppressFinalize(this);
         }
 
+        /// <summary>
+        /// Gets the low-level twain object.
+        /// </summary>
+        public TWAIN TWAIN { get { return _twain; } }
+
         #region event callbacks
 
         private void HandleUIThreadAction(Action action)
@@ -85,7 +90,7 @@ namespace NTwain
             while (true)
             {
                 // Try to get an event...
-                twdeviceevent = default(TW_DEVICEEVENT);
+                twdeviceevent = default;
                 sts = _twain.DatDeviceevent(DG.CONTROL, MSG.GET, ref twdeviceevent);
                 if (sts != STS.SUCCESS)
                 {
@@ -124,6 +129,17 @@ namespace NTwain
             get { return _twain.GetState(); }
         }
 
+        /// <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 sts = _twain.DatStatus(DG.CONTROL, MSG.GET, ref stat);
+            return stat;
+        }
+
         /// <summary>
         /// Opens the TWAIN data source manager.
         /// This needs to be done before anything else.
@@ -152,7 +168,7 @@ namespace NTwain
             var list = new List<TW_IDENTITY>();
             if (State > STATE.S2)
             {
-                var twidentity = default(TW_IDENTITY);
+                TW_IDENTITY twidentity = default;
                 STS sts;
 
                 for (sts = _twain.DatIdentity(DG.CONTROL, MSG.GETFIRST, ref twidentity);
@@ -172,7 +188,7 @@ namespace NTwain
         {
             get
             {
-                var twidentity = default(TW_IDENTITY);
+                TW_IDENTITY twidentity = default;
                 var sts = _twain.DatIdentity(DG.CONTROL, MSG.GETDEFAULT, ref twidentity);
                 if (sts == STS.SUCCESS) return twidentity;
                 return null;
@@ -189,7 +205,8 @@ namespace NTwain
         }
 
         /// <summary>
-        /// Gets the currently open device.
+        /// Gets or sets the currently open device.
+        /// Setting it will try to open it.
         /// </summary>
         public TW_IDENTITY? CurrentDevice
         {
@@ -197,7 +214,7 @@ namespace NTwain
             {
                 if (State > STATE.S3)
                 {
-                    var twidentity = default(TW_IDENTITY);
+                    TW_IDENTITY twidentity = default;
                     if (TWAIN.CsvToIdentity(ref twidentity, _twain.GetDsIdentity()))
                     {
                         return twidentity;
@@ -205,6 +222,15 @@ namespace NTwain
                 }
                 return null;
             }
+            set
+            {
+                StepDown(STATE.S3);
+                if (value.HasValue)
+                {
+                    var twidentity = value.Value;
+                    _twain.DatIdentity(DG.CONTROL, MSG.OPENDS, ref twidentity);
+                }
+            }
         }
 
         /// <summary>
@@ -213,7 +239,7 @@ namespace NTwain
         /// <param name="state"></param>
         public void StepDown(STATE state)
         {
-            var twpendingxfers = default(TW_PENDINGXFERS);
+            TW_PENDINGXFERS twpendingxfers = default;
 
             // Make sure we have something to work with...
             if (_twain == null)
@@ -239,14 +265,14 @@ namespace NTwain
             // 5 --> 4
             if ((_twain.GetState() == STATE.S5) && (state < STATE.S5))
             {
-                var twuserinterface = default(TW_USERINTERFACE);
+                TW_USERINTERFACE twuserinterface = default;
                 _twain.DatUserinterface(DG.CONTROL, MSG.DISABLEDS, ref twuserinterface);
             }
 
             // 4 --> 3
             if ((_twain.GetState() == STATE.S4) && (state < STATE.S4))
             {
-                var twidentity = default(TW_IDENTITY);
+                TW_IDENTITY twidentity = default;
                 TWAIN.CsvToIdentity(ref twidentity, _twain.GetDsIdentity());
                 _twain.DatIdentity(DG.CONTROL, MSG.CLOSEDS, ref twidentity);
             }

samples/Net5Console/Net5Console.csproj

@@ -0,0 +1,12 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net5.0-windows</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\NTwain\NTwain.csproj" />
+  </ItemGroup>
+
+</Project>

samples/Net5Console/Program.cs

@@ -0,0 +1,38 @@
+using NTwain;
+using System;
+using System.Reflection;
+
+namespace Net5Console
+{
+    class Program
+    {
+        static void Main(string[] args)
+        {
+            using (var twain = new TwainSession(Assembly.GetExecutingAssembly(), null, IntPtr.Zero))
+            {
+                if (twain.Open() == TWAINWorkingGroup.STS.SUCCESS)
+                {
+                    Console.WriteLine("Opened DSM");
+                    Console.WriteLine("Default device:");
+                    Console.WriteLine($"\t{twain.DefaultDevice}");
+                    Console.WriteLine("All devices:");
+                    foreach (var dev in twain.GetDevices())
+                    {
+                        Console.WriteLine($"\t{dev}");
+                    }
+                    Console.WriteLine("Current device:");
+                    Console.WriteLine($"\t{twain.CurrentDevice}");
+                    twain.CurrentDevice = twain.DefaultDevice;
+                    Console.WriteLine("Current device after setting:");
+                    Console.WriteLine($"\t{twain.CurrentDevice}");
+                }
+                else
+                {
+                    Console.Error.WriteLine("Failed to open DSM");
+                }
+                Console.WriteLine("Test Ended");
+            }
+        
+        }
+    }
+}