WCF：序列化和反序列化泛型集合 [英] WCF: Serializing and Deserializing generic collections

问题描述

我有一个一流的团队持有一个通用的清单：

I have a class Team that holds a generic list:

[DataContract(Name = "TeamDTO", IsReference = true)]
public class Team
{
    [DataMember]
    private IList<Person> members = new List<Person>();

    public Team()
    {
        Init();
    }

    private void Init()
    {
        members = new List<Person>();
    }

    [System.Runtime.Serialization.OnDeserializing]
    protected void OnDeserializing(StreamingContext ctx)
    {
        Log("OnDeserializing of Team called");
        Init();
        if (members != null) Log(members.ToString());
    }

    [System.Runtime.Serialization.OnSerializing]
    private void OnSerializing(StreamingContext ctx)
    {
        Log("OnSerializing of Team called");
        if (members != null) Log(members.ToString());
    }

    [System.Runtime.Serialization.OnDeserialized]
    protected void OnDeserialized(StreamingContext ctx)
    {
        Log("OnDeserialized of Team called");
        if (members != null) Log(members.ToString());
    }

    [System.Runtime.Serialization.OnSerialized]
    private void OnSerialized(StreamingContext ctx)
    {
        Log("OnSerialized of Team called");
        Log(members.ToString());
    }

当我在一个WCF服务中使用这个类，我得到下面的日志输出

When I use this class in a WCF service, I get following log output

OnSerializing of Team called    
System.Collections.Generic.List 1[XXX.Person]

OnSerialized of Team called    
System.Collections.Generic.List 1[XXX.Person]

OnDeserializing of Team called    
System.Collections.Generic.List 1[XXX.Person]

OnDeserialized of Team called    
XXX.Person[]

反序列化后成员是一个数组，不再是一个通用的清单，尽管字段类型为IList的＆LT;>（？！） 当我尝试这个对象发回了WCF服务，我得到的日志输出

After the deserialization members is an Array and no longer a generic list although the field type is IList<> (?!) When I try to send this object back over the WCF service I get the log output

OnSerializing of Team called
XXX.Person[]

在此我的单元测试崩溃了System.ExecutionEngineException，这意味着WCF服务不能够序列化数组。 （也许是因为它预期的IList＆LT;>）

After this my unit test crashes with a System.ExecutionEngineException, which means the WCF service is not able to serialize the array. (maybe because it expected a IList<>)

所以，我的问题是：是否有人知道为什么我的IList＆LT的类型;>为反序列化后的数组，为什么我不能在那之后不再序列化我的球队对象

So, my question is: Does anybody know why the type of my IList<> is an array after deserializing and why I can't serialize my Team object any longer after that?

感谢

推荐答案

您已经遇到的的DataContractSerializer 陷阱之一。

You've run into one of the DataContractSerializer gotchas.

修正：您的私有成员声明更改为：

Fix: Change your private member declaration to:

[DataMember]
private List<Person> members = new List<Person>();

或属性更改为：

OR change the property to:

[DataMember()]
public IList<Person> Feedback {
    get { return m_Feedback; }
    set {
        if ((value != null)) {
            m_Feedback = new List<Person>(value);

        } else {
            m_Feedback = new List<Person>();
        }
    }
}

和它的工作。微软连接错误是<一个href="https://connect.microsoft.com/wcf/feedback/details/433569/wcf-throws-an-executionengineexception-when-returning-an-array-as-ilist-t"相对=nofollow>这里

And it will work. The Microsoft Connect bug is here

当你反序列化对象发生此问题的的IList＆LT; T＆GT; 数据成员，然后尝试再次序列相同的实例

This problem occurs when you deserialize an object with an IList<T> DataMember and then try to serialize the same instance again.

如果你想看到一些很酷的东西：

If you want to see something cool:

using System;
using System.Collections.Generic;

class TestArrayAncestry
{
    static void Main(string[] args)
    {
        int[] values = new[] { 1, 2, 3 };        
        Console.WriteLine("int[] is IList<int>: {0}", values is IList<int>);
    }
}

这将打印 INT []是的IList＆LT; INT计算值：真。

我怀疑这可能是你看到它回来作为反序列化后的数组的原因，但是这是不直观。

I suspect this is possibly the reason you see it come back as an array after deserialization, but it is quite non-intuitive.

如果你调用Add（）方法的的IList＆LT; INT＆GT; 虽然阵，它抛出 NotSupportedException异常。

If you call the Add() method on the IList<int> of the array though, it throws NotSupportedException.

其中一个.NET怪癖。

One of those .NET quirks.

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