PR #13987 from AviaAv: enable config for context on C#

Author: Nir-Az

wrappers/csharp/Intel.RealSense/Context.cs

@@ -52,6 +52,18 @@ public Context()
             onDevicesChangedCallback = new rs2_devices_changed_callback(OnDevicesChangedInternal);
         }
 
+        /// <summary>
+        /// Initializes a new instance of the <see cref="Context"/> class with json_settings.
+        /// 
+        /// </summary>
+        public Context(string json_settings)
+        {
+            object error;
+
+            handle = NativeMethods.rs2_create_context_ex(ApiVersion, json_settings, out error);
+            onDevicesChangedCallback = new rs2_devices_changed_callback(OnDevicesChangedInternal);
+        }
+
         /// <summary>
         /// Gets the safe handle
         /// </summary>

wrappers/csharp/Intel.RealSense/NativeMethods.cs

@@ -527,6 +527,9 @@ internal static MemCpyDelegate GetMethod()
         [DllImport(dllName, CallingConvention = CallingConvention.Cdecl)]
         internal static extern ContextHandle rs2_create_context(int api_version, [MarshalAs(UnmanagedType.CustomMarshaler, MarshalTypeRef = typeof(ErrorMarshaler))] out object error);
 
+        [DllImport(dllName, CallingConvention = CallingConvention.Cdecl)]
+        internal static extern ContextHandle rs2_create_context_ex(int api_version, [MarshalAs(UnmanagedType.LPStr)] string json_settings, [MarshalAs(UnmanagedType.CustomMarshaler, MarshalTypeRef = typeof(ErrorMarshaler))] out object error);
+
         [DllImport(dllName, CallingConvention = CallingConvention.Cdecl)]
         internal static extern void rs2_delete_context(ContextHandle context);
 

wrappers/csharp/tutorial/capture/Window.xaml.cs

@@ -54,6 +54,8 @@ public CaptureWindow()
                 using (var ctx = new Context())
                 {
                     var devices = ctx.QueryDevices();
+                    Console.WriteLine("There are {0} connected RealSense devices.", devices.Count);
+                    if (devices.Count == 0) return;
                     var dev = devices[0];
 
                     Console.WriteLine("\nUsing device 0, an {0}", dev.Info[CameraInfo.Name]);