Add helpers to SettingsDictionary

--HG--
branch : dev

src/Orchard/ContentManagement/MetaData/Models/SettingsDictionary.cs

@@ -1,4 +1,5 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using System.Web.Mvc;
 
 namespace Orchard.ContentManagement.MetaData.Models {
@@ -6,11 +7,7 @@ namespace Orchard.ContentManagement.MetaData.Models {
         public SettingsDictionary() { }
         public SettingsDictionary(IDictionary<string, string> dictionary) : base(dictionary) { }
 
-        public T GetModel<T>() where T : class, new() {
+        private T TryGetModel<T>(string key) where T : class {
-            return GetModel<T>(typeof(T).Name);
-        }
-
-        public T GetModel<T>(string key) where T : class, new() {
             var binder = new DefaultModelBinder();
             var controllerContext = new ControllerContext();
             var context = new ModelBindingContext {
@@ -18,7 +15,24 @@ namespace Orchard.ContentManagement.MetaData.Models {
                 ModelName = key,
                 ValueProvider = new DictionaryValueProvider<string>(this, null)
             };
-            return (T)binder.BindModel(controllerContext, context) ?? new T();
+            return (T)binder.BindModel(controllerContext, context);
+
+        }
+
+        public T GetModel<T>() where T : class, new() {
+            return GetModel<T>(typeof(T).Name);
+        }
+
+        public T GetModel<T>(string key) where T : class, new() {
+            return TryGetModel<T>(key) ?? new T();
+        }
+
+        public bool ContainsModel<T>() where T : class {
+            return TryGetModel<T>(typeof(T).Name) != null;
+        }
+
+        public bool ContainsModel<T>(string key) where T : class {
+            return TryGetModel<T>(key) != null;
         }
     }
 }