/Trunk/MvcExtensions/ExtensionMethod/ViewDataDictionaryExtensions.cs

#region Copyright

// Copyright (c) 2009 - 2010, Kazi Manzur Rashid <kazimanzurrashid@gmail.com>.

// This source is subject to the Microsoft Public License. 

// See http://www.microsoft.com/opensource/licenses.mspx#Ms-PL. 

// All other rights reserved.

#endregion



namespace MvcExtensions

{

    using System.Collections.Generic;

    using System.Linq;

    using System.Web.Mvc;

    using System.Web.Script.Serialization;



    /// <summary>

    /// Defines an static class which contains extension methods of <see cref="ViewDataDictionary"/>.

    /// </summary>

    public static class ViewDataDictionaryExtensions

    {

        /// <summary>

        /// Gets the value against the specified type name.

        /// </summary>

        /// <typeparam name="TValue">The type of the value.</typeparam>

        /// <param name="instance">The instance.</param>

        /// <returns></returns>

        public static TValue Get<TValue>(this ViewDataDictionary instance)

        {

            return Get<TValue>(instance, MakeKey<TValue>());

        }



        /// <summary>

        /// Gets the value that is stored against the specified key.

        /// </summary>

        /// <typeparam name="TValue">The type of the value.</typeparam>

        /// <param name="instance">The instance.</param>

        /// <param name="key">The key.</param>

        /// <returns></returns>

        public static TValue Get<TValue>(this ViewDataDictionary instance, string key)

        {

            return Get(instance, key, default(TValue));

        }



        /// <summary>

        /// Gets the value that is stored against the specified key, if the key does not exists it will return the provided default value.

        /// </summary>

        /// <typeparam name="TValue">The type of the value.</typeparam>

        /// <param name="instance">The instance.</param>

        /// <param name="key">The key.</param>

        /// <param name="defaultValue">The default value.</param>

        /// <returns></returns>

        public static TValue Get<TValue>(this ViewDataDictionary instance, string key, TValue defaultValue)

        {

            Invariant.IsNotNull(instance, "instance");



            return instance.ContainsKey(key) ? (TValue)instance[key] : defaultValue;

        }



        /// <summary>

        /// Sets the value against the specified type.

        /// </summary>

        /// <typeparam name="TValue">The type of the value.</typeparam>

        /// <param name="instance">The instance.</param>

        /// <param name="value">The value.</param>

        public static void Set<TValue>(this ViewDataDictionary instance, TValue value)

        {

            Set(instance, MakeKey<TValue>(), value);

        }



        /// <summary>

        /// Sets the value against the specified key.

        /// </summary>

        /// <typeparam name="TValue">The type of the value.</typeparam>

        /// <param name="instance">The instance.</param>

        /// <param name="key">The key.</param>

        /// <param name="value">The value.</param>

        public static void Set<TValue>(this ViewDataDictionary instance, string key, TValue value)

        {

            Invariant.IsNotNull(instance, "instance");



            instance[key] = value;

        }



        /// <summary>

        /// Determines whether  the specified type exists.

        /// </summary>

        /// <typeparam name="TValue">The type of the value.</typeparam>

        /// <param name="instance">The instance.</param>

        /// <returns>

        /// <c>true</c> if [contains] [the specified instance]; otherwise, <c>false</c>.

        /// </returns>

        public static bool Contains<TValue>(this ViewDataDictionary instance)

        {

            Invariant.IsNotNull(instance, "instance");



            return instance.ContainsKey(MakeKey<TValue>());

        }



        /// <summary>

        /// Removes the specified type.

        /// </summary>

        /// <typeparam name="TValue">The type of the value.</typeparam>

        /// <param name="instance">The instance.</param>

        public static bool Remove<TValue>(this ViewDataDictionary instance)

        {

            Invariant.IsNotNull(instance, "instance");



            return instance.Remove(MakeKey<TValue>());

        }



        /// <summary>

        /// Convert the view data into json string.

        /// </summary>

        /// <param name="instance">The instance.</param>

        /// <returns></returns>

        public static string ToJson(this ViewDataDictionary instance)

        {

            return ToJson(instance, null);

        }



        /// <summary>

        /// Convert the view data into json string.

        /// </summary>

        /// <param name="instance">The instance.</param>

        /// <param name="jsonConverters">The json converters.</param>

        /// <returns></returns>

        public static string ToJson(this ViewDataDictionary instance, IEnumerable<JavaScriptConverter> jsonConverters)

        {

            return AsSerializable(instance).ToJson(jsonConverters);

        }



        /// <summary>

        /// Convert the view data into a serializable object.

        /// </summary>

        /// <param name="instance">The instance.</param>

        /// <returns></returns>

        public static object AsSerializable(this ViewDataDictionary instance)

        {

            Invariant.IsNotNull(instance, "instance");



            var viewData = instance.Select(pair => new { key = pair.Key, value = pair.Value })

                                   .ToList();



            var modelStates = instance.ModelState.IsValid ?

                              null :

                              instance.ModelState.Select(ms => new { key = ms.Key, errors = ms.Value.Errors.Select(error => (error.Exception == null) ? error.ErrorMessage : error.Exception.Message).Where(error => !string.IsNullOrEmpty(error)) })

                                                 .Where(ms => ms.errors.Any()) // No need to include model state that does not have any errors

                                                 .ToList();



            var result = new { viewData = viewData.Any() ? viewData : null, model = instance.Model, modelStates = ((modelStates != null) && modelStates.Any()) ? modelStates : null };



            return result;

        }



        private static string MakeKey<TValue>()

        {

            return typeof(TValue).FullName;

        }

    }

}