WCF 复杂 JSON INPUT 错误(QueryStringConverter 不可转换)

Question

我在将复杂 JSON 用作 WCF 服务中的参数时遇到问题。

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

有以下契约(Contract):

[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; }
    }
}

使用以下网址:

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'.

Answer 1

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。见 this response来自 ASP.NET 论坛中的 Microsoft 技术 - 这与您的情况类似。

根据您如何删除服务方法，似乎更合适的动词是 POST 或 PUT，您可以输入 CompositeType请求正文中的有效负载。但我猜你的意图。

通过将查询字符串类型从 CompositeType 更改，我能够使您的代码正常工作并仍然使用 GET至 String然后将 JSON 字符串反序列化为 CompositeType通过使用 ASP.NET JavaScriptSerializer类。 (你可以在这里使用你最喜欢的 JSON 帮助类——我偏爱 JSON.NET ，但我也听说 FlexJson 也很好。)

我没有接触你的 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;
    }

}

我希望这会有所帮助。如果您对此有其他疑问，请告诉我。