title: Passing data from a jquery ajax request to a wcf service fails deserialization?
body: <p>I use the following code to call a wcf service. If i call a (test) method that takes no parameters, but returns a string it works fine. If i add a parameter to my method i get a wierd error:</p>
  
  <blockquote>
    <p>{"ExceptionDetail":{"HelpLink":null,"InnerException":null,"Message":"The token '\"' was expected but found '''.","StackTrace":" at System.Xml.XmlExceptionHelper.ThrowXmlException(XmlDictionaryReader reader, String res, String arg1, String arg2, String arg3)\u000d\u000a at System.Xml.XmlExceptionHelper.ThrowTokenExpected(XmlDictionaryReader reader, String expected, Char found)\u000d\u000a at System.Runtime.Serialization.Json.XmlJsonReader.ParseStartElement()\u000d\u000a at System.Runtime.Serialization.Json.XmlJsonReader.Read()\u000d\u000a at System.ServiceModel.Dispatcher.DataContractJsonSerializerOperationFormatter.DeserializeBodyCore(XmlDictionaryReader reader, Object[] parameters, Boolean isRequest)\u000d\u000a at System.ServiceModel.Dispatcher.DataContractJsonSerializerOperationFormatter.DeserializeBody(XmlDictionaryReader reader, MessageVersion version, String action, MessageDescription messageDescription, Object[] parameters, Boolean isRequest)\u000d\u000a at System.ServiceModel.Dispatcher.OperationFormatter.DeserializeBodyContents(Message message, Object[] parameters, Boolean isRequest)\u000d\u000a at System.ServiceModel.Dispatcher.OperationFormatter.DeserializeRequest(Message message, Object[] parameters)\u000d\u000a at System.ServiceModel.Dispatcher.DemultiplexingDispatchMessageFormatter.DeserializeRequest(Message message, Object[] parameters)\u000d\u000a at System.ServiceModel.Dispatcher.UriTemplateDispatchFormatter.DeserializeRequest(Message message, Object[] parameters)\u000d\u000a at System.ServiceModel.Dispatcher.CompositeDispatchFormatter.DeserializeRequest(Message message, Object[] parameters)\u000d\u000a at System.ServiceModel.Dispatcher.DispatchOperationRuntime.DeserializeInputs(MessageRpc&amp; rpc)\u000d\u000a at System.ServiceModel.Dispatcher.DispatchOperationRuntime.InvokeBegin(MessageRpc&amp; rpc)\u000d\u000a at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage5(MessageRpc&amp; rpc)\u000d\u000a at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage4(MessageRpc&amp; rpc)\u000d\u000a at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage3(MessageRpc&amp; rpc)\u000d\u000a at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage2(MessageRpc&amp; rpc)\u000d\u000a at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage1(MessageRpc&amp; rpc)\u000d\u000a at System.ServiceModel.Dispatcher.MessageRpc.Process(Boolean isOperationContextSet)","Type":"System.Xml.XmlException"},"ExceptionType":"System.Xml.XmlException","Message":"The token '\"' was expected but found '''.","StackTrace":" at System.Xml.XmlExceptionHelper.ThrowXmlException(XmlDictionaryReader reader, String res, String arg1, String arg2, String arg3)\u000d\u000a at System.Xml.XmlExceptionHelper.ThrowTokenExpected(XmlDictionaryReader reader, String expected, Char found)\u000d\u000a at System.Runtime.Serialization.Json.XmlJsonReader.ParseStartElement()\u000d\u000a at System.Runtime.Serialization.Json.XmlJsonReader.Read()\u000d\u000a at System.ServiceModel.Dispatcher.DataContractJsonSerializerOperationFormatter.DeserializeBodyCore(XmlDictionaryReader reader, Object[] parameters, Boolean isRequest)\u000d\u000a at System.ServiceModel.Dispatcher.DataContractJsonSerializerOperationFormatter.DeserializeBody(XmlDictionaryReader reader, MessageVersion version, String action, MessageDescription messageDescription, Object[] parameters, Boolean isRequest)\u000d\u000a at System.ServiceModel.Dispatcher.OperationFormatter.DeserializeBodyContents(Message message, Object[] parameters, Boolean isRequest)\u000d\u000a at System.ServiceModel.Dispatcher.OperationFormatter.DeserializeRequest(Message message, Object[] parameters)\u000d\u000a at System.ServiceModel.Dispatcher.DemultiplexingDispatchMessageFormatter.DeserializeRequest(Message message, Object[] parameters)\u000d\u000a at System.ServiceModel.Dispatcher.UriTemplateDispatchFormatter.DeserializeRequest(Message message, Object[] parameters)\u000d\u000a at System.ServiceModel.Dispatcher.CompositeDispatchFormatter.DeserializeRequest(Message message, Object[] parameters)\u000d\u000a at System.ServiceModel.Dispatcher.DispatchOperationRuntime.DeserializeInputs(MessageRpc&amp; rpc)\u000d\u000a at System.ServiceModel.Dispatcher.DispatchOperationRuntime.InvokeBegin(MessageRpc&amp; rpc)\u000d\u000a at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage5(MessageRpc&amp; rpc)\u000d\u000a at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage4(MessageRpc&amp; rpc)\u000d\u000a at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage3(MessageRpc&amp; rpc)\u000d\u000a at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage2(MessageRpc&amp; rpc)\u000d\u000a at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage1(MessageRpc&amp; rpc)\u000d\u000a at System.ServiceModel.Dispatcher.MessageRpc.Process(Boolean isOperationContextSet)"}</p>
  </blockquote>
  
  <p>My jquery looks like this, but i tried changing the actual data which i send as a string serialized json (as you can see) to a pure json object with the same sad result.</p>
  
  <pre><code>$.ajax({
      type: "POST",
      contentType: "application/json; charset=utf-8",
      url: "ajax/Statistics.svc/Get7DaysStatistics",
      dataType: "json",
      data: "{'customerId': '2'}",
      timeout: 10000,
      success: function(obj) { updateStatistics(obj.d); },
      error: function(xhr) {
          if (xhr.responseText)          
              $("body").html(xhr.responseText);
          else
              alert('unknown error');
          return;
      }
  });
  </code></pre>
  
  <p>The wcf service looks like this:</p>
  
  <pre><code>    [SuppressMessage("Microsoft.Performance", "CA1822:MarkMembersAsStatic"), OperationContract]
      public string Get7DaysStatistics(string customerId)
      {
          Debug.WriteLine(customerId);
          return "Test done";
      }
  </code></pre>
  
  <p>It's placed in a a class with the following attributes:</p>
  
  <pre><code>[ServiceContract(Namespace = "")]
  [AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)]
  </code></pre>
  
  <p>I won't list the configuration in the web.config to keep this long message "short" but i can post it if anybody thinks they can use it - i just want to stress that i CAN call a method and get a result - string or even a json object i can read from as long as i DON'T pass any data to the wcf service.</p>