如何避免循环引用，而序列化实体框架类 [英] How do I avoid a circular reference while serializing Entity Framework class

问题描述

我使用实体框架4的MVC-3（RC1）应用程序。

I have an MVC-3 (RC1) application using Entity Framework 4.

我想从一个控制器动作返回一个JSON对象。这个目的是通过其他的目的，这显然返回参考引用

I wish to return a JSON object from a controller action. This object is referenced by other objects, which obviously return the reference.

我因此收到以下循环引用错误：

I thus receive the following circular reference error:

中的服务器错误'/'应用。

Server Error in '/' Application.

中检测到循环引用
  而序列化类型的对象
  Application.Models.ReferenceObject。

A circular reference was detected while serializing an object of type 'Application.Models.ReferenceObject'.

说明：未处理的异常
  的执行过程中发生
  当前Web请求。请检查
  堆栈跟踪有关的详细信息
  该错误以及它起源于
  在code。

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

异常详细信息：
  System.InvalidOperationException：一
  而检测到循环引用
  序列类型的对象
  Application.Models.ReferenceObject。

Exception Details: System.InvalidOperationException: A circular reference was detected while serializing an object of type 'Application.Models.ReferenceObject'.

注：应用＆安培; ReferenceObject 显然替代实际的命名空间/对象。

NB: Application & ReferenceObject are obviously replacements for the actual namespace / object.

据<一个href=\"http://stackoverflow.com/questions/1468584/circular-reference-exception-when-serializing-linq-to-sql-classes\"标题=堆栈溢出：循环引用异常序列化的LINQ to SQL类时>堆栈溢出：LINQ序列化时，循环引用例外SQL类的，这可以通过使用JSON.Net加以克服;不过，我想避免这种情况，而是试图排除对象被序列化违规的参考属性。

According to Stack Overflow: Circular reference exception when serializing LINQ to SQL classes, this can be overcome using JSON.Net; however I would like to avoid this and instead try to exclude the offending reference properties from the object being serialized.

这是什么意思？

我想要做这样的事情：

IList<ReferenceObject> list = Repository.GetReferenceObjects();
return Json(list.**<method>**("ObjectsReferencingThis"));

其中， **＆LT;方法＆gt; ** 一些方法，做相反的的 的ObjectQuery（Of T）已.INCLUDE 方法和 ObjectsReferencingThis 是导致循环引用的属性。

where **<method>** is some method that does the opposite to the ObjectQuery(Of T).Include method and ObjectsReferencingThis is the property that is causing the circular reference.

注：我不希望删除这些属性或创建作为波苏斯这只会影响JSON序列

NB: I do not wish to remove these properties or create POCOs as this only affects the Json serialization.

任何人能帮助吗？

：）

推荐答案

我的时候对我的previous项目之一，曾遇到过类似问题。
以下是我落得这样做：

I had a similar problem when worked on one of my previous project. Here is what I ended up doing:

IList<Product> list = Repository.GetProducts();
  var collection = products.Select(product => new
        {
            id = product.Id,
            name = product.Name,
            detailUrl = product.DetailUrl,
            imageLargeUrl = product.ThumbNailUrl,
            tagtitle = product.Name.ToUpper(),
            tagheader = "Words our cherished patrons use to describe this product",
            tagwords = from tag in product.Tags group tag by tag.Name into words select new { name =          words.Key, weight = words.Count() }
        });

 var result = new {id = inquiry.Id, products = collection, };
 return this.Jsonp(result);

下面是结果的Json会是什么样子：

Here is how the result Json would look like:

{
"id" : 2,
"products" : [{
    "id" : "3605970008857",
    "name" : "TITLE1",
    "detailUrl" : "http://www.urlhere.com",
    "tagwords" : [{
        "name" : "roses",
        "weight" : 1
    },
    {
        "name" : "cotton",
        "weight" : 1
    },
    {
        "name" : "happy",
        "weight" : 1
    }]
},
{
    "id" : "3605970019891",
    "name" : "TITLE2",
    "detailUrl" : "http://www.urlhere.com",
    "tagwords" : []
}],

}

您也可以从你引用的对象将结果添加任何其他属性，如你所愿，在你的JSON对象中显示：）

You can also add any other properties from you referenced objects to the result as you wish,to be shown in your Json object :)

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