WCF DataContractSerializer无法获取合同属性...为什么不呢? [英] WCF DataContractSerializer doesn't pick up contract attributes... why not?

问题描述

我有以下类型，可以在WCF中用作消息合同:

I have the following type which I use as a message contract in WCF:

[MessageContract(IsWrapped = true, 
                 WrapperNamespace = "http://example.com/services", 
                 WrapperName = "EchoRequest")]
public class EchoRequest
{
    public EchoRequest() { }
    public EchoRequest(String value)
    {
        Value = value;
    }

    [MessageBodyMember(Name = "Value", 
                       Namespace = "http://example.com/services", 
                       Order = 0)]
    public String Value { get; set; }
}

当我使用 svcutil.exe 生成这种类型的代理时，我得到了一个客户端，该客户端能够与托管它的服务进行通信，并且元素上的XML名称空间根据邮件合同属性.

When I generate a proxy to this type using svcutil.exe, I get a client which is able to communicate to a service which hosts it, with the XML namespaces on the elements correct according to the Message Contract attributes.

当我在其实例上使用Message.CreateMessage(...)时，名称空间将还原为默认名称( http://schemas.datacontract.org/2004/07/.. .).当我使用DataContractSerializer的实例时，会发生相同的事情.我尝试将名称空间传递给DataContractSerializer构造函数，并且只有包装器包含在名称空间中:

When I use Message.CreateMessage(...) on an instance of it, the namespaces revert to the default (http://schemas.datacontract.org/2004/07/...). When I use an instance of DataContractSerializer, the same thing happens. I try to pass a namespace to the DataContractSerializer constructor, and only the wrapper gets included in the namespace:

var requestMessage = new EchoRequest("hello, world!");
var serializer = new DataContractSerializer(typeof(EchoRequest), 
                                            "EchoRequest", 
                                            "http://example.com/services");
var stream = new MemoryStream();
serializer.WriteObject(stream, requestMessage);
var data = Encoding.UTF8.GetString(stream.ToArray());

此时，数据"为:

<EchoRequest xmlns="http://example.com/services"
             xmlns:a="http://schemas.datacontract.org/2004/07/TestClient"
             xmlns:i="http://www.w3.org/2001/XMLSchema-instance">
    <a:Value>hello, world!</a:Value>
</EchoRequest>

为什么DataContractSerializer似乎忽略了MessageContract属性? svcutil 如何完成这项工作?

Why does the DataContractSerializer appear to ignore the MessageContract attributes? How does svcutil get this work?

推荐答案

这是因为消息合同不是数据合同，所以数据合同使用不同的属性来标记其类.尝试使用类型化的消息转换器；

It's because message contracts are not data contracts, data contracts use different attributes to mark their classes. Try using a typed message converter;

EchoRequest echoRequest = new EchoRequest{ value = "Hello" };

TypedMessageConverter echoMessageConverter = TypedMessageConverter.Create(
                 typeof(echoRequest),
                 "YourActionNameHere",
                 "http://example.com/services");
Message request = echoMessageConverter.ToMessage(
    echoRequest,MessageVersion.Soap11);

然后您将准备好一条消息，可以根据需要拉出请求正文.

You'll then have a message all ready to go and can pull the request body out if you need to.

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