Modifying ModelStateDictionary to derive from IDictionary

* Reintroducing methods that weren't ported over earlier

src/Microsoft.AspNet.Mvc.ModelBinding/ModelStateDictionary.cs

@@ -1,13 +1,14 @@
 using System;
+using System.Collections;
 using System.Collections.Generic;
 using System.Linq;
 using Microsoft.AspNet.Mvc.ModelBinding.Internal;
 
 namespace Microsoft.AspNet.Mvc.ModelBinding
 {
-    public class ModelStateDictionary : Dictionary<string, ModelState>
+    public class ModelStateDictionary : IDictionary<string, ModelState>
     {
-        private readonly Dictionary<string, ModelState> _innerDictionary = new Dictionary<string, ModelState>(StringComparer.OrdinalIgnoreCase);
+        private readonly IDictionary<string, ModelState> _innerDictionary = new Dictionary<string, ModelState>(StringComparer.OrdinalIgnoreCase);
 
         public ModelStateDictionary()
         {
@@ -21,17 +22,50 @@ namespace Microsoft.AspNet.Mvc.ModelBinding
             }
         }
 
+        #region IDictionary properties
+        public int Count
+        {
+            get { return _innerDictionary.Count; }
+        }
+
+        public bool IsReadOnly
+        {
+            get { return _innerDictionary.IsReadOnly; }
+        }
+
+        public ICollection<string> Keys
+        {
+            get { return _innerDictionary.Keys; }
+        }
+
+        public ICollection<ModelState> Values
+        {
+            get { return _innerDictionary.Values; }
+        }
+        #endregion
+
         public bool IsValid
         {
             get { return Values.All(modelState => modelState.Errors.Count == 0); }
         }
 
-        public void AddModelError(string key, Exception exception)
+        public ModelState this[[NotNull] string key]
+        {
+            get
+            {
+                ModelState value;
+                _innerDictionary.TryGetValue(key, out value);
+                return value;
+            }
+            set { _innerDictionary[key] = value; }
+        }
+
+        public void AddModelError([NotNull] string key, [NotNull] Exception exception)
         {
             GetModelStateForKey(key).Errors.Add(exception);
         }
 
-        public void AddModelError(string key, string errorMessage)
+        public void AddModelError([NotNull] string key, [NotNull] string errorMessage)
         {
             GetModelStateForKey(key).Errors.Add(errorMessage);
         }
@@ -39,7 +73,7 @@ namespace Microsoft.AspNet.Mvc.ModelBinding
         public bool IsValidField([NotNull] string key)
         {
             // if the key is not found in the dictionary, we just say that it's valid (since there are no errors)
-            foreach (var entry in DictionaryHelper.FindKeysWithPrefix(this, key))
+            foreach (var entry in DictionaryHelper.FindKeysWithPrefix(_innerDictionary, key))
             {
                 if (entry.Value.Errors.Count != 0)
                 {
@@ -49,6 +83,24 @@ namespace Microsoft.AspNet.Mvc.ModelBinding
             return true;
         }
 
+        public void Merge(ModelStateDictionary dictionary)
+        {
+            if (dictionary == null)
+            {
+                return;
+            }
+
+            foreach (var entry in dictionary)
+            {
+                this[entry.Key] = entry.Value;
+            }
+        }
+
+        public void SetModelValue([NotNull] string key, [NotNull] ValueProviderResult value)
+        {
+            GetModelStateForKey(key).Value = value;
+        }
+
         private ModelState GetModelStateForKey([NotNull] string key)
         {
             ModelState modelState;
@@ -60,9 +112,63 @@ namespace Microsoft.AspNet.Mvc.ModelBinding
 
             return modelState;
         }
-        public void SetModelValue(string key, ValueProviderResult value)
+
+        #region IDictionary members
+        public void Add(KeyValuePair<string, ModelState> item)
         {
-            GetModelStateForKey(key).Value = value;
+            _innerDictionary.Add(item);
         }
+
+        public void Add([NotNull] string key, [NotNull] ModelState value)
+        {
+            _innerDictionary.Add(key, value);
+        }
+
+        public void Clear()
+        {
+            _innerDictionary.Clear();
+        }
+
+        public bool Contains(KeyValuePair<string, ModelState> item)
+        {
+            return _innerDictionary.Contains(item);
+        }
+
+        public bool ContainsKey([NotNull] string key)
+        {
+            return _innerDictionary.ContainsKey(key);
+        }
+
+        public void CopyTo([NotNull] KeyValuePair<string, ModelState>[] array, int arrayIndex)
+        {
+            _innerDictionary.CopyTo(array, arrayIndex);
+        }
+
+        
+        public bool Remove(KeyValuePair<string, ModelState> item)
+        {
+            return _innerDictionary.Remove(item);
+        }
+
+        public bool Remove([NotNull] string key)
+        {
+            return _innerDictionary.Remove(key);
+        }
+
+        public bool TryGetValue([NotNull] string key, out ModelState value)
+        {
+            return _innerDictionary.TryGetValue(key, out value);
+        }
+
+        public IEnumerator<KeyValuePair<string, ModelState>> GetEnumerator()
+        {
+            return _innerDictionary.GetEnumerator();
+        }
+
+        IEnumerator IEnumerable.GetEnumerator()
+        {
+            return GetEnumerator();
+        }
+        #endregion
     }
 }