c# - Deserialize JSON object sent from Android app to WCF webservice

Question

I'm trying to send a JSON object to my webservice method, the method is defined like this:

public String SendTransaction(string trans)
{
            var json_serializer = new JavaScriptSerializer();
            Transaction transObj = json_serializer.Deserialize<Transaction>(trans);
            return transObj.FileName;       
}

Where I want to return the FileName of this JSON string that I got as a parameter.

The code for the android application:

HttpPost request = new HttpPost(
                "http://10.118.18.88:8080/Service.svc/SendTransaction");
        request.setHeader("Accept", "application/json");
        request.setHeader("Content-type", "application/json");

        // Build JSON string
        JSONStringer jsonString;

        jsonString = new JSONStringer()
                .object().key("imei").value("2323232323").key("filename")
                .value("Finger.NST").endObject();

        Log.i("JSON STRING: ", jsonString.toString());

        StringEntity entity;

        entity = new StringEntity(jsonString.toString(), "UTF-8");

        entity.setContentEncoding(new BasicHeader(HTTP.CONTENT_TYPE,
                "application/json"));
        entity.setContentType("application/json");

        request.setEntity(entity);

        // Send request to WCF service
        DefaultHttpClient httpClient = new DefaultHttpClient();

        HttpResponse response = httpClient.execute(request);
        HttpEntity httpEntity = response.getEntity();
        String xml = EntityUtils.toString(httpEntity);

        Log.i("Response: ", xml);
        Log.d("WebInvoke", "Status : " + response.getStatusLine());

I only get a long html file out, which tells me The server has encountered an error processing the request. And the status code is HTTP/1.1 400 Bad Request

My Transaction class is defined in C# like this:

 [DataContract]
public class Transaction
{
    [DataMember(Name ="imei")]
    public string Imei { get; set; }

    [DataMember (Name="filename")]
    public string FileName { get; set; }
}

How can I accomplish this in the right way?

EDIT, this is my web.config

 <?xml version="1.0"?>
<configuration>

  <appSettings>
    <add key="aspnet:UseTaskFriendlySynchronizationContext" value="true" />
  </appSettings>
  <system.web>
    <compilation debug="true" targetFramework="4.5" />
    <httpRuntime targetFramework="4.5"/>
  </system.web>
  <system.serviceModel>
    <behaviors>

          <endpointBehaviors>
            <behavior name="httpBehavior">
                <webHttp />
            </behavior >
        </endpointBehaviors>

      <serviceBehaviors>
        <behavior name="">
          <!-- To avoid disclosing metadata information, set the values below to false before deployment -->
          <serviceMetadata httpGetEnabled="true" httpsGetEnabled="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>
    </behaviors>

    <serviceHostingEnvironment multipleSiteBindingsEnabled="true"/>
    <services>
      <service name="Service.Service">
        <endpoint address="" behaviorConfiguration="httpBehavior" binding="webHttpBinding" contract="Service.IService"/>
      </service>
    </services>

    <protocolMapping>
        <add binding="webHttpBinding" scheme="http" />
    </protocolMapping>

    <!--<serviceHostingEnvironment aspNetCompatibilityEnabled="true" multipleSiteBindingsEnabled="true" />-->
  </system.serviceModel>
  <system.webServer>
  <!-- <modules runAllManagedModulesForAllRequests="true"/>-->
    <!--
        To browse web app root directory during debugging, set the value below to true.
        Set to false before deployment to avoid disclosing web app folder information.
      -->
    <directoryBrowse enabled="true"/>
  </system.webServer>

</configuration>

Answer 1

@Tobias, This is not an answer. But since it was a little bit long for comment, I post it here. Maybe it can help to diagnose your problem. [A full working code].

public void TestWCFService()
{
    //Start Server
    Task.Factory.StartNew(
        (_) =>{
            Uri baseAddress = new Uri("http://localhost:8080/Test");
            WebServiceHost host = new WebServiceHost(typeof(TestService), baseAddress);
            host.Open();
        },null,TaskCreationOptions.LongRunning).Wait();


    //Client
    var jsonString = new JavaScriptSerializer().Serialize(new { xaction = new { Imei = "121212", FileName = "Finger.NST" } });
    WebClient wc = new WebClient();
    wc.Headers.Add("Content-Type", "application/json");
    var result = wc.UploadString("http://localhost:8080/Test/Hello", jsonString);
}

[ServiceContract]
public class TestService
{
    [OperationContract]
    [WebInvoke(RequestFormat = WebMessageFormat.Json, ResponseFormat = WebMessageFormat.Json, BodyStyle = WebMessageBodyStyle.Wrapped)]
    public User Hello(Transaction xaction)
    {
        return new User() { Id = 1, Name = "Joe", Xaction = xaction };
    }

    public class User
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public Transaction Xaction { get; set; }
    }

    public class Transaction
    {
        public string Imei { get; set; }
        public string FileName { get; set; }
    }
}