WCF 复杂 JSON 输入错误（无法通过 QueryStringConverter 转换）

我在将复杂 JSON 作为 WCF 服务中的参数工作时遇到问题。

在 Visual Studio 2008 SP1 中使用 Microsoft.Net 3.5 SP1

签订以下合同：

[ServiceContract]
public interface IService1
{

    [OperationContract]
    [WebGet(UriTemplate="GetDataUsingDataContract?composite={composite}", 
        BodyStyle=WebMessageBodyStyle.Wrapped, 
        RequestFormat=WebMessageFormat.Json, ResponseFormat = WebMessageFormat.Json)]
    CompositeType GetDataUsingDataContract(CompositeType composite);

    // TODO: Add your service operations here
}

// Use a data contract as illustrated in the sample below to add composite types to service operations
[DataContract]
public class CompositeType
{
    string boolValue = "true";
    string stringValue = "Hello ";

    [DataMember]
    public string BoolValue
    {
        get { return boolValue; }
        set { boolValue = value; }
    }

    [DataMember]
    public string StringValue
    {
        get { return stringValue; }
        set { stringValue = value; }
    }
}

使用以下 URL：

http://localhost:1122/Service1.svc/GetDataUsingDataContract?composite={"BoolValue":"True","StringValue":"Hello"}

使用端点配置：

<system.serviceModel>
    <services>
        <service name="WebHTTPBindingExample.Service1" behaviorConfiguration="WebHTTPBindingExample.Service1Behavior">
            <host>
                <baseAddresses>
                    <add baseAddress="http://localhost:8731/Design_Time_Addresses/WebHTTPBindingExample/Service1/"/>
                </baseAddresses>
            </host>
            <!-- Service Endpoints -->
            <!-- Unless fully qualified, address is relative to base address supplied above -->
            <!--<endpoint address="" binding="wsHttpBinding" contract="WebHTTPBindingExample.IService1">
                --><!-- 
      Upon deployment, the following identity element should be removed or replaced to reflect the 
      identity under which the deployed service runs.  If removed, WCF will infer an appropriate identity 
      automatically.
  --><!--
                <identity>
                    <dns value="localhost"/>
                </identity>
            </endpoint>-->
            <endpoint address="Web" behaviorConfiguration="ChatAspNetAjaxBehavior" binding="webHttpBinding" name="ajaxEndpoint" contract="WebHTTPBindingExample.IService1"/>
            <!-- Metadata Endpoints -->
            <!-- The Metadata Exchange endpoint is used by the service to describe itself to clients. -->
            <!-- This endpoint does not use a secure binding and should be secured or removed before deployment -->
            <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange"/>
        </service>
    </services>
    <behaviors>
        <serviceBehaviors>
            <behavior name="WebHTTPBindingExample.Service1Behavior">
                <!-- To avoid disclosing metadata information, 
  set the value below to false and remove the metadata endpoint above before deployment -->
                <serviceMetadata httpGetEnabled="True"/>
                <!-- To receive exception details in faults for debugging purposes, 
  set the value below to true.  Set to false before deployment 
  to avoid disclosing exception information -->
                <serviceDebug includeExceptionDetailInFaults="False"/>
            </behavior>
        </serviceBehaviors>
        <endpointBehaviors>
            <behavior name="ChatAspNetAjaxBehavior">
                <webHttp/>
            </behavior>
        </endpointBehaviors>
    </behaviors>
</system.serviceModel>

我收到以下错误：

Operation 'GetDataUsingDataContract' in contract 'IService1' has a query variable named 'composite' of type 'WebHTTPBindingExample.CompositeType', but type 'WebHTTPBindingExample.CompositeType' is not convertible by 'QueryStringConverter'.  Variables for UriTemplate query values must have types that can be converted by 'QueryStringConverter'.

我不相信您可以通过这种方式使用 WCF 在查询字符串上传递复杂类型。看这个回应 http://forums.asp.net/t/1408622.aspx/1?Passing+complex+types+as+a+parameter来自 ASP.NET 论坛中的 Microsoft 技术人员 - 这与您的情况类似。

根据您删除服务方法的方式，似乎更合适的动词是 POST 或 PUT，您可以将您的CompositeType请求正文中的负载。但我猜测你的意图。

我能够通过更改查询字符串类型来使您的代码工作并且仍然使用 GETCompositeType to String然后将 JSON 字符串反序列化为CompositeType通过使用 ASP.NETJavaScriptSerializer班级。 （您可以在这里使用您最喜欢的 JSON 帮助器类——我偏向于JSON.NET http://james.newtonking.com/pages/json-net.aspx，但我也听到FlexJson http://flexjson.sourceforge.net/javadoc/flexjson/JSONSerializer.html也非常好。）

我没有碰你的 web.config （除了让它在我的本地测试应用程序中工作）。我唯一的变化是服务方法签名和服务方法的实现。

[ServiceContract]
public interface IService1
{

    [OperationContract]
    [WebGet(UriTemplate = "GetDataUsingDataContract?composite={composite}",
        BodyStyle = WebMessageBodyStyle.Wrapped,
        RequestFormat = WebMessageFormat.Json, ResponseFormat = WebMessageFormat.Json)]
    CompositeType GetDataUsingDataContract(String composite);

    // TODO: Add your service operations here
}


public class Service1 : IService1
{
    public CompositeType GetDataUsingDataContract(String composite)
    {
        //use the JavaScriptSerializer to convert the string to a CompositeType instance
        JavaScriptSerializer jscript = new JavaScriptSerializer();
        CompositeType newComp = jscript.Deserialize<CompositeType>(composite);
        newComp.StringValue += " NEW!";
        return newComp;
    }

}

我希望这有帮助。如果您对此还有其他疑问，请告诉我。