.Net MVC5异步请求Entity Framework 无限循环解决方法

.Net MVC5异步请求Entity Framework 无限循环解决方法

　　Entity Framework 存在一对多、多对多之间的关系，相互依赖，在返回JSON数据时往往会出现相互引用造成的无限循环问题，对于第三方提供的json序列还通过特性、序列化配置可以解决掉无限循环的问题，因此我们可以利用第三方库解决掉MVC返回JSON无限循环的问题。

　　我们可以利用Newtonsoft.Json 的JsonSerializerSettings类进行序列化的设置

　　

　　对于ReferenceLoopHandling枚举类型

 #region 程序集 Newtonsoft.Json, Version=4.5.0.0, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed
 // E:\VsGit\DigitizationPlatform\dll\Newtonsoft.Json.dll
 #endregion

 namespace Newtonsoft.Json
 {
     //
     // 摘要:
     //     Specifies reference loop handling options for the Newtonsoft.Json.JsonSerializer.
     public enum ReferenceLoopHandling
     {
         //
         // 摘要:
         //     Throw a Newtonsoft.Json.JsonSerializationException when a loop is encountered.
         Error = ,
         //
         // 摘要:
         //     Ignore loop references and do not serialize.
         Ignore = ,
         //
         // 摘要:
         //     Serialize loop references.
         Serialize =
     }
 }

　　我们可以设置JsonSerializerSettings

  　　　　　　　　 JsonSerializerSettings set = new JsonSerializerSettings();
                 set.Formatting = Formatting.Indented;
                 set.DateFormatString = "yyyy-MM-dd HH:mm:ss";
                 //set.MaxDepth = 10;
                 set.ReferenceLoopHandling = ReferenceLoopHandling.Ignore;

　　这样我们便可以解决JsonResult返回JSON无限循环问题了

重写MVC -> JsonResult：

 using Newtonsoft.Json;
 using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Text;
 using System.Threading.Tasks;
 using System.Web;
 using System.Web.Mvc;

 namespace Goldwind.Framework.Web.OverrideExtension
 {
     public class MyJsonResult: JsonResult
     {
         public MyJsonResult() { }
         public MyJsonResult(object Data) {
             this.Data = Data;
         }
         public MyJsonResult(object Data, JsonRequestBehavior JsonRequestBehavior = JsonRequestBehavior.DenyGet) :this(Data){
             this.JsonRequestBehavior = JsonRequestBehavior;
         }
         public MyJsonResult(object Data, string ContentType,Encoding ContentEncoding = null, JsonRequestBehavior JsonRequestBehavior = JsonRequestBehavior.DenyGet) :this(Data,JsonRequestBehavior) {
             this.ContentType = ContentType;
             if(ContentEncoding != null)
             {
                 this.ContentEncoding = ContentEncoding;
             }
         }
         public override void ExecuteResult(ControllerContext context)
         {
             if(this.JsonRequestBehavior == JsonRequestBehavior.DenyGet
                 && string.Compare(context.HttpContext.Request.HttpMethod,"Get",true) == )
             {
                 throw new InvalidOperationException();
             }
             HttpResponseBase response = context.HttpContext.Response;
             response.ContentType = string.IsNullOrEmpty(this.ContentType) ?
                 "application/json" : this.ContentType;
             if(this.ContentEncoding != null)
             {
                 response.ContentEncoding = this.ContentEncoding;
             }
             if(null != this.Data)
             {
                 JsonSerializerSettings set = new JsonSerializerSettings();
                 set.Formatting = Formatting.Indented;
                 set.DateFormatString = "yyyy-MM-dd HH:mm:ss";
                 //set.MaxDepth = 10;
                 set.ReferenceLoopHandling = ReferenceLoopHandling.Ignore;
                 response.Write(JsonConvert.SerializeObject(this.Data,set));
             }
         }
     }
 }