(chocolateyGH-533) Added ability to notify when language is changed

Source/ChocolateyGui/ChocolateyGui.csproj

@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <Project ToolsVersion="12.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
   <PropertyGroup>
@@ -310,6 +310,7 @@
     <Compile Include="Utilities\Extensions\MvvmExtensions.cs" />
     <Compile Include="Utilities\IDataGridColumnComparer.cs" />
     <Compile Include="Utilities\ResourceReader.cs" />
+    <Compile Include="Utilities\TranslationSource.cs" />
     <Compile Include="ViewModels\AboutViewModel.cs" />
     <Compile Include="ViewModels\ISourceViewModelBase.cs" />
     <Compile Include="Utilities\Converters\BooleanToVisibility.cs" />

Source/ChocolateyGui/Utilities/TranslationSource.cs

@@ -0,0 +1,40 @@
+// --------------------------------------------------------------------------------------------------------------------
+// <copyright company="Chocolatey" file="TranslationSource.cs">
+//   Copyright 2014 - Present Rob Reynolds, the maintainers of Chocolatey, and RealDimensions Software, LLC
+// </copyright>
+// --------------------------------------------------------------------------------------------------------------------
+
+using System.Globalization;
+using System.Resources;
+using ChocolateyGui.Base;
+using ChocolateyGui.Properties;
+
+namespace ChocolateyGui.Utilities
+{
+    public sealed class TranslationSource : ObservableBase
+    {
+        private readonly ResourceManager resourceManager = Resources.ResourceManager;
+        private CultureInfo currentCulture = null;
+
+        public static TranslationSource Instance { get; } = new TranslationSource();
+
+        public CultureInfo CurrentCulture
+        {
+            get
+            {
+                return currentCulture;
+            }
+
+            set
+            {
+                if (currentCulture != value)
+                {
+                    currentCulture = value;
+                    NotifyPropertyChanged(string.Empty); // We call with an empty string on purpose to force an update for all resource strings.
+                }
+            }
+        }
+
+        public string this[string key] => resourceManager.GetString(key, CurrentCulture);
+    }
+}