mvc使用Newtonsoft.Json還原序列化json資料

標籤：mvc還原序列化   mvc全域還原序列化   valueproviderfactori   global 還原序列化   newtonsoft.json   

mvc中預設使用的json返回序列化工具是JsonValueProviderFactory，JsonValueProviderFactory繼承自ValueProviderFactory抽象類別。JsonValueProviderFactory使用的序列化類別庫是System.Web.Script.Serialization。現在我們來寫一個自己的方序列話工具，採用的是Newtonsoft.Json序列化和還原序列化工具。

JsonValueProviderFactory代碼具體如下：

using System;using System.Collections;using System.Collections.Generic;using System.Dynamic;using System.Globalization;using System.IO;using System.Web.Mvc;using Newtonsoft.Json;using Newtonsoft.Json.Converters;namespace Aft.Build.MvcWeb.Common{    public class JsonNetValueProviderFactory : ValueProviderFactory    {        public override IValueProvider GetValueProvider(ControllerContext controllerContext)        {            // first make sure we have a valid context            if (controllerContext == null)                throw new ArgumentNullException("controllerContext");            // now make sure we are dealing with a json request            if (!controllerContext.HttpContext.Request.ContentType.StartsWith("application/json", StringComparison.OrdinalIgnoreCase))                return null;            // get a generic stream reader (get reader for the http stream)            var streamReader = new StreamReader(controllerContext.HttpContext.Request.InputStream);            // convert stream reader to a JSON Text Reader            var jsonReader = new JsonTextReader(streamReader);            // tell JSON to read            if (!jsonReader.Read())                return null;            // make a new Json serializer            var jsonSerializer = new JsonSerializer();            // add the dyamic object converter to our serializer            jsonSerializer.Converters.Add(new ExpandoObjectConverter());            // use JSON.NET to deserialize object to a dynamic (expando) object            Object jsonObject;            // if we start with a "[", treat this as an array            if (jsonReader.TokenType == JsonToken.StartArray)                jsonObject = jsonSerializer.Deserialize<List<ExpandoObject>>(jsonReader);            else                jsonObject = jsonSerializer.Deserialize<ExpandoObject>(jsonReader);            // create a backing store to hold all properties for this deserialization            var backingStore = new Dictionary<string, object>(StringComparer.OrdinalIgnoreCase);            // add all properties to this backing store            AddToBackingStore(backingStore, String.Empty, jsonObject);            // return the object in a dictionary value provider so the MVC understands it            return new DictionaryValueProvider<object>(backingStore, CultureInfo.CurrentCulture);        }        private static void AddToBackingStore(Dictionary<string, object> backingStore, string prefix, object value)        {            var d = value as IDictionary<string, object>;            if (d != null)            {                foreach (var entry in d)                {                    AddToBackingStore(backingStore, MakePropertyKey(prefix, entry.Key), entry.Value);                }                return;            }            var l = value as IList;            if (l != null)            {                for (int i = 0; i < l.Count; i++)                {                    AddToBackingStore(backingStore, MakeArrayKey(prefix, i), l[i]);                }                return;            }            // primitive            backingStore[prefix] = value;        }        private static string MakeArrayKey(string prefix, int index)        {            return prefix + "[" + index.ToString(CultureInfo.InvariantCulture) + "]";        }        private static string MakePropertyKey(string prefix, string propertyName)        {            return (String.IsNullOrEmpty(prefix)) ? propertyName : prefix + "." + propertyName;        }    }}

然後把JsonValueProviderFactory註冊給全域json資料還原序列化使用：

在Global.asax檔案Application_Start方法中添加如下兩行代碼：

ValueProviderFactories.Factories.Remove(ValueProviderFactories.Factories.OfType<JsonValueProviderFactory>().FirstOrDefault());            ValueProviderFactories.Factories.Add(new JsonNetValueProviderFactory());

第一句是移除原來的JsonValueProviderFactory還原序列化，第二句是添加自己的還原序列化工具。

總結及注意事項：

1.mvc用戶端資料到伺服器段的資料類型轉換都是在通過ValueProviderFactories來註冊的。

2.切記mvc中通過ajax來傳到伺服器段的資料報文頭記得一定要Content-Type:application/json，不然不會使用我們上面自己的JsonNetValueProviderFactory還原序列化工具