Make ValueProviderResult a string-ish struct

Author: rynowak

NuGet.Config

@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <configuration>
   <packageSources>
     <add key="AspNetVNext" value="https://www.myget.org/F/aspnetlitedev/api/v2" />

src/Microsoft.AspNet.Mvc.Abstractions/ModelBinding/ModelState.cs

@@ -3,17 +3,29 @@
 
 namespace Microsoft.AspNet.Mvc.ModelBinding
 {
+    /// <summary>
+    /// An entry in a <see cref="ModelStateDictionary"/>.
+    /// </summary>
     public class ModelState
     {
-        private readonly ModelErrorCollection _errors = new ModelErrorCollection();
+        /// <summary>
+        /// Gets the raw value from the request associated with this entry.
+        /// </summary>
+        public object RawValue { get; set; }
 
-        public ValueProviderResult Value { get; set; }
+        /// <summary>
+        /// Gets the set of values contained in <see cref="RawValue"/>, joined into a comma-separated string.
+        /// </summary>
+        public string AttemptedValue { get; set; }
 
-        public ModelErrorCollection Errors
-        {
-            get { return _errors; }
-        }
+        /// <summary>
+        /// Gets the <see cref="ModelErrorCollection"/> for this entry.
+        /// </summary>
+        public ModelErrorCollection Errors { get; } = new ModelErrorCollection();
 
+        /// <summary>
+        /// Gets or sets the <see cref="ModelValidationState"/> for this entry.
+        /// </summary>
         public ModelValidationState ValidationState { get; set; }
     }
 }

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

@@ -4,6 +4,7 @@
 using System;
 using System.Collections;
 using System.Collections.Generic;
+using System.Globalization;
 using System.Linq;
 using Microsoft.AspNet.Mvc.Abstractions;
 using Microsoft.Framework.Internal;
@@ -213,6 +214,7 @@ public bool TryAddModelError([NotNull] string key, [NotNull] Exception exception
                 // Convert FormatExceptions to Invalid value messages.
                 ModelState modelState;
                 TryGetValue(key, out modelState);
+
                 string errorMessage;
                 if (modelState == null)
                 {
@@ -221,7 +223,7 @@ public bool TryAddModelError([NotNull] string key, [NotNull] Exception exception
                 else
                 {
                     errorMessage = Resources.FormatModelError_InvalidValue_MessageWithModelValue(
-                        modelState.Value.AttemptedValue,
+                        modelState.AttemptedValue,
                         key);
                 }
 
@@ -359,14 +361,50 @@ public void Merge(ModelStateDictionary dictionary)
         }
 
         /// <summary>
-        /// Sets the value for the <see cref="ModelState"/> with the specified <paramref name="key"/> to the
-        /// specified <paramref name="value"/>.
+        /// Sets the of <see cref="ModelState.RawValue"/> and <see cref="ModelState.AttemptedValue"/> for 
+        /// the <see cref="ModelState"/> with the specified <paramref name="key"/>.
         /// </summary>
         /// <param name="key">The key for the <see cref="ModelState"/> entry.</param>
-        /// <param name="value">The value to assign.</param>
-        public void SetModelValue([NotNull] string key, [NotNull] ValueProviderResult value)
+        /// <param name="rawvalue">The raw value for the <see cref="ModelState"/> entry.</param>
+        /// <param name="attemptedValue">
+        /// The values of <param name="rawValue"/> in a comma-separated <see cref="string"/>.
+        /// </param>
+        public void SetModelValue([NotNull] string key, object rawValue, string attemptedValue)
         {
-            GetModelStateForKey(key).Value = value;
+            var modelState = GetModelStateForKey(key);
+            modelState.RawValue = rawValue;
+            modelState.AttemptedValue = attemptedValue;
+        }
+
+        /// <summary>
+        /// Sets the value for the <see cref="ModelState"/> with the specified <paramref name="key"/>.
+        /// </summary>
+        /// <param name="key">The key for the <see cref="ModelState"/> entry</param>
+        /// <param name="valueProviderResult">
+        /// A <see cref="ValueProviderResult"/> with data for the <see cref="ModelState"/> entry.
+        /// </param>
+        public void SetModelValue([NotNull] string key, ValueProviderResult valueProviderResult)
+        {
+            // Avoid creating a new array for rawvalue if there's only one value.
+            object rawValue;
+            if (valueProviderResult == ValueProviderResult.None)
+            {
+                rawValue = null;
+            }
+            else if (valueProviderResult.Value != null)
+            {
+                rawValue = valueProviderResult.Value;
+            }
+            else if (valueProviderResult.Length == 1)
+            {
+                rawValue = valueProviderResult.Values[0];
+            }
+            else
+            {
+                rawValue = valueProviderResult.Values;
+            }
+
+            SetModelValue(key, rawValue, (string)valueProviderResult);
         }
 
         /// <summary>