Support for HelpText localization with ResourceType property.

src/CommandLine/BaseAttribute.cs

@@ -12,8 +12,9 @@ public abstract class BaseAttribute : Attribute
         private int min;
         private int max;
         private object @default;
-        private string helpText;
+        private Infrastructure.LocalizableAttributeProperty helpText;
         private string metaValue;
+        private Type resourceType;
 
         /// <summary>
         /// Initializes a new instance of the <see cref="CommandLine.BaseAttribute"/> class.
@@ -22,8 +23,9 @@ protected internal BaseAttribute()
         {
             min = -1;
             max = -1;
-            helpText = string.Empty;
+            helpText = new Infrastructure.LocalizableAttributeProperty(nameof(HelpText));
             metaValue = string.Empty;
+            resourceType = null;
         }
 
         /// <summary>
@@ -90,15 +92,15 @@ public object Default
         /// </summary>
         public string HelpText
         {
-            get { return helpText; }
+            get { return helpText.Value; }
             set
             {
                 if (value == null)
                 {
                     throw new ArgumentNullException("value");
                 }
 
-                helpText = value;
+                helpText.Value = value;
             }
         }
 
@@ -127,5 +129,18 @@ public bool Hidden
             get;
             set;
         }
+
+        /// <summary>
+        /// Gets or sets the <see cref="System.Type"/> that contains the resources for <see cref="HelpText"/>.
+        /// </summary>
+        public Type ResourceType
+        {
+            get { return resourceType; }
+            set
+            {
+                resourceType =
+                helpText.ResourceType = value;
+            }
+        }
     }
 }

src/CommandLine/CommandLine.csproj

@@ -84,6 +84,7 @@
     <Compile Include="Core\Verb.cs" />
     <Compile Include="Infrastructure\ExceptionExtensions.cs" />
     <Compile Include="Infrastructure\FSharpOptionHelper.cs" />
+    <Compile Include="Infrastructure\LocalizableAttributeProperty.cs" />
     <Compile Include="Infrastructure\PopsicleSetter.cs" />
     <Compile Include="Infrastructure\ReferenceEqualityComparer.cs" />
     <Compile Include="Infrastructure\ReflectionHelper.cs" />
@@ -169,8 +170,16 @@
         </Reference>
       </ItemGroup>
     </When>
-    <When Condition="$(TargetFrameworkIdentifier) == '.NETFramework' And ($(TargetFrameworkVersion) == 'v4.0' Or $(TargetFrameworkVersion) == 'v4.0.3' Or $(TargetFrameworkVersion) == 'v4.5' Or $(TargetFrameworkVersion) == 'v4.5.1' Or $(TargetFrameworkVersion) == 'v4.5.2' Or $(TargetFrameworkVersion) == 'v4.5.3' Or $(TargetFrameworkVersion) == 'v4.6' Or $(TargetFrameworkVersion) == 'v4.6.1' Or $(TargetFrameworkVersion) == 'v4.6.2' Or $(TargetFrameworkVersion) == 'v4.6.3' Or $(TargetFrameworkVersion) == 'v4.7' Or $(TargetFrameworkVersion) == 'v4.7.1')" />
-    <When Condition="($(TargetFrameworkIdentifier) == '.NETCore') Or ($(TargetFrameworkIdentifier) == 'MonoAndroid' And ($(TargetFrameworkVersion) == 'v1.0' Or $(TargetFrameworkVersion) == 'v2.2' Or $(TargetFrameworkVersion) == 'v2.3' Or $(TargetFrameworkVersion) == 'v4.0.3' Or $(TargetFrameworkVersion) == 'v4.1' Or $(TargetFrameworkVersion) == 'v4.2' Or $(TargetFrameworkVersion) == 'v4.3' Or $(TargetFrameworkVersion) == 'v4.4' Or $(TargetFrameworkVersion) == 'v5.0' Or $(TargetFrameworkVersion) == 'v5.1' Or $(TargetFrameworkVersion) == 'v6.0' Or $(TargetFrameworkVersion) == 'v7.0' Or $(TargetFrameworkVersion) == 'v7.1' Or $(TargetFrameworkVersion) == 'v8.0')) Or ($(TargetFrameworkIdentifier) == 'MonoTouch') Or ($(TargetFrameworkIdentifier) == '.NETCoreApp' And ($(TargetFrameworkVersion) == 'v1.0' Or $(TargetFrameworkVersion) == 'v1.1' Or $(TargetFrameworkVersion) == 'v2.0')) Or ($(TargetFrameworkIdentifier) == '.NETStandard' And ($(TargetFrameworkVersion) == 'v1.1' Or $(TargetFrameworkVersion) == 'v1.2' Or $(TargetFrameworkVersion) == 'v1.3' Or $(TargetFrameworkVersion) == 'v1.4' Or $(TargetFrameworkVersion) == 'v1.5' Or $(TargetFrameworkVersion) == 'v1.6' Or $(TargetFrameworkVersion) == 'v2.0')) Or ($(TargetFrameworkProfile) == 'Profile7') Or ($(TargetFrameworkProfile) == 'Profile44') Or ($(TargetFrameworkIdentifier) == 'Xamarin.iOS') Or ($(TargetFrameworkIdentifier) == 'Xamarin.Mac') Or ($(TargetFrameworkIdentifier) == 'Xamarin.tvOS') Or ($(TargetFrameworkIdentifier) == 'Xamarin.watchOS')">
+    <When Condition="$(TargetFrameworkIdentifier) == '.NETFramework' And ($(TargetFrameworkVersion) == 'v4.0' Or $(TargetFrameworkVersion) == 'v4.0.3' Or $(TargetFrameworkVersion) == 'v4.5' Or $(TargetFrameworkVersion) == 'v4.5.1' Or $(TargetFrameworkVersion) == 'v4.5.2' Or $(TargetFrameworkVersion) == 'v4.5.3' Or $(TargetFrameworkVersion) == 'v4.6' Or $(TargetFrameworkVersion) == 'v4.6.1' Or $(TargetFrameworkVersion) == 'v4.6.2' Or $(TargetFrameworkVersion) == 'v4.6.3' Or $(TargetFrameworkVersion) == 'v4.7' Or $(TargetFrameworkVersion) == 'v4.7.1' Or $(TargetFrameworkVersion) == 'v4.7.2')">
+      <ItemGroup>
+        <Reference Include="FSharp.Core">
+          <HintPath>..\..\packages\FSharp.Core\lib\net40\FSharp.Core.dll</HintPath>
+          <Private>True</Private>
+          <Paket>True</Paket>
+        </Reference>
+      </ItemGroup>
+    </When>
+    <When Condition="($(TargetFrameworkIdentifier) == '.NETCore') Or ($(TargetFrameworkIdentifier) == 'MonoAndroid' And ($(TargetFrameworkVersion) == 'v1.0' Or $(TargetFrameworkVersion) == 'v2.2' Or $(TargetFrameworkVersion) == 'v2.3' Or $(TargetFrameworkVersion) == 'v4.0.3' Or $(TargetFrameworkVersion) == 'v4.1' Or $(TargetFrameworkVersion) == 'v4.2' Or $(TargetFrameworkVersion) == 'v4.3' Or $(TargetFrameworkVersion) == 'v4.4' Or $(TargetFrameworkVersion) == 'v5.0' Or $(TargetFrameworkVersion) == 'v5.1' Or $(TargetFrameworkVersion) == 'v6.0' Or $(TargetFrameworkVersion) == 'v7.0' Or $(TargetFrameworkVersion) == 'v7.1' Or $(TargetFrameworkVersion) == 'v8.0' Or $(TargetFrameworkVersion) == 'v8.1' Or $(TargetFrameworkVersion) == 'v9.0')) Or ($(TargetFrameworkIdentifier) == 'MonoTouch') Or ($(TargetFrameworkIdentifier) == '.NETCoreApp' And ($(TargetFrameworkVersion) == 'v1.0' Or $(TargetFrameworkVersion) == 'v1.1' Or $(TargetFrameworkVersion) == 'v2.0' Or $(TargetFrameworkVersion) == 'v2.1' Or $(TargetFrameworkVersion) == 'v2.2' Or $(TargetFrameworkVersion) == 'v3.0')) Or ($(TargetFrameworkIdentifier) == '.NETStandard' And ($(TargetFrameworkVersion) == 'v1.1' Or $(TargetFrameworkVersion) == 'v1.2' Or $(TargetFrameworkVersion) == 'v1.3' Or $(TargetFrameworkVersion) == 'v1.4' Or $(TargetFrameworkVersion) == 'v1.5' Or $(TargetFrameworkVersion) == 'v1.6' Or $(TargetFrameworkVersion) == 'v2.0')) Or ($(TargetFrameworkProfile) == 'Profile7') Or ($(TargetFrameworkProfile) == 'Profile44') Or ($(TargetFrameworkIdentifier) == 'Xamarin.iOS') Or ($(TargetFrameworkIdentifier) == 'Xamarin.Mac') Or ($(TargetFrameworkIdentifier) == 'Xamarin.tvOS') Or ($(TargetFrameworkIdentifier) == 'Xamarin.watchOS')">
       <ItemGroup>
         <Reference Include="FSharp.Core">
           <HintPath>..\..\packages\FSharp.Core\lib\portable-net45+netcore45\FSharp.Core.dll</HintPath>

src/CommandLine/Infrastructure/LocalizableAttributeProperty.cs

@@ -0,0 +1,62 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Reflection;
+using System.Text;
+
+namespace CommandLine.Infrastructure
+{
+    internal class LocalizableAttributeProperty
+    {
+        private string _propertyName;
+        private string _value;
+        private Type _type;
+        private PropertyInfo _localizationPropertyInfo;
+
+        public LocalizableAttributeProperty(string propertyName)
+        {
+            _propertyName = propertyName;
+        }
+
+        public string Value
+        {
+            get { return GetLocalizedValue(); }
+            set
+            {
+                _localizationPropertyInfo = null;
+                _value = value;
+            }
+        }
+
+        public Type ResourceType
+        {
+            set
+            {
+                _localizationPropertyInfo = null;
+                _type = value;
+            }
+        }
+
+        private string GetLocalizedValue()
+        {
+            if (String.IsNullOrEmpty(_value) || _type == null)
+                return _value;
+            if (_localizationPropertyInfo == null)
+            {
+                // Static class IsAbstract                
+#if NETSTANDARD1_5
+                if (!_type.GetTypeInfo().IsVisible)
+#else
+                if (!_type.IsVisible)
+#endif
+                    throw new ArgumentException("Invalid resource type", _propertyName);
+                PropertyInfo propertyInfo = _type.GetProperty(_value, BindingFlags.Public | BindingFlags.GetProperty | BindingFlags.Static);
+                if (propertyInfo == null || !propertyInfo.CanRead || propertyInfo.PropertyType != typeof(string))
+                    throw new ArgumentException("Invalid resource property name", _propertyName);
+                _localizationPropertyInfo = propertyInfo;
+            }
+            return (string)_localizationPropertyInfo.GetValue(null, null);
+        }
+    }
+
+}