防止StackOverflowException，同时将Entity Framework对象图序列化为Json [英] Preventing StackOverflowException while serializing Entity Framework object graph into Json

问题描述

我要序列化），因为这会导致一个非常长且难以维护的代码片段）。

解决方案

您有冲突的关注，EF模型优化用于存储您的数据模型在RDBMS，而不是序列化 - 这是什么角色单独的DTO将播放。否则，您的客户端将绑定到您的数据库，您的数据模型上的每一个更改都有可能打破您现有的服务客户端。

据说，正确的事情将保持您映射到的单独的DTO，以定义您希望模型看起来像外部世界的所需形状（又称线形式）。

ServiceStack.Common 包括简化映射实体到DTO的内置映射函数（即TranslateTo / PopulateFrom），反之亦然。下面是一个显示此示例的示例：

https ：//groups.google.com/d/msg/servicestack/BF-egdVm3M8/0DXLIeDoVJEJ

另一种方法是装饰要序列化的字段在您的数据模型上使用[DataContract] / [DataMember]字段。任何未归因于[DataMember]的属性不会被序列化 - 因此您可以使用它来隐藏导致StackOverflowException的循环引用。

I want to serialize an Entity Framework Self-Tracking Entities full object graph (parent + children in one to many relationships) into Json.

For serializing I use ServiceStack.JsonSerializer.

This is how my database looks like (for simplicity, I dropped all irrelevant fields):

I fetch a full profile graph in this way:

public Profile GetUserProfile(Guid userID)
{
    using (var db = new AcmeEntities())
    {
        return db.Profiles.Include("ProfileImages").Single(p => p.UserId == userId);
    }
}

The problem is that attempting to serialize it:

Profile profile = GetUserProfile(userId);
ServiceStack.JsonSerializer.SerializeToString(profile);

produces a StackOverflowException. I believe that this is because EF provides an infinite model that screws the serializer up. That is, I can techincally call: profile.ProfileImages[0].Profile.ProfileImages[0].Profile ... and so on.

How can I "flatten" my EF object graph or otherwise prevent ServiceStack.JsonSerializer from running into stack overflow situation?

Note: I don't want to project my object into an anonymous type (like these suggestions) because that would introduce a very long and hard-to-maintain fragment of code).

解决方案

You have conflicting concerns, the EF model is optimized for storing your data model in an RDBMS, and not for serialization - which is what role having separate DTOs would play. Otherwise your clients will be binded to your Database where every change on your data model has the potential to break your existing service clients.

With that said, the right thing to do would be to maintain separate DTOs that you map to which defines the desired shape (aka wireformat) that you want the models to look like from the outside world.

ServiceStack.Common includes built-in mapping functions (i.e. TranslateTo/PopulateFrom) that simplifies mapping entities to DTOs and vice-versa. Here's an example showing this:

https://groups.google.com/d/msg/servicestack/BF-egdVm3M8/0DXLIeDoVJEJ

The alternative is to decorate the fields you want to serialize on your Data Model with [DataContract] / [DataMember] fields. Any properties not attributed with [DataMember] wont be serialized - so you would use this to hide the cyclical references which are causing the StackOverflowException.

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