Escaped JSON response with [WebMethod]

问题:

The JSON response from the following code is wrongly escaped as described below.

My webmethod is like this:

    [WebMethod (Description="doc here")]
    [ScriptMethod(ResponseFormat=ResponseFormat.Json)] 
    public string responseMyObject() {
            if (!Setup()) return "";

            ...
            Proxy pu = new Proxy(...);
...

            string toReturn = JavaScriptConvert.SerializeObject(pu.getMyObject());
            Console.WriteLine(toReturn);
            return toReturn;
    }

from the console I get:

{"field1":vaule1,"field2":value2}

from JS:

$.ajax({
    type: "POST",
    url: "/myapi/myClass.asmx/responseMyObject",
    data: "{}",
    contentType: "application/json; charset=utf-8",
    dataType: "json",
    success: function(msg) {
                    var object = msg.d;
                    alert(object.field1);
    }
});

The problem is that in the HTTP response header I can see that the JSON response is wrongly (?) escaped in the following way:

{"d":"{\"field1\":value1,\"field2\":value2}"}

What's strange is that the console print is fine (but not yet encapsulated in {d: ...}

{"field1":value1,"field2":value2}

With similar code, if I call a [WebMethod] that returns basic types (no object) the JSON response is ok. Like:

{"d":8080}

回答1:

[WebService]
[ScriptService]
public class MyWebService : WebService
{    

  [WebMethod (Description="doc here")]    
  [ScriptMethod( UseHttpGet=false, ResponseFormat=ResponseFormat.Json)]     
  public MyObjectType responseMyObject() 
  {
      Proxy pu = new Proxy(...);

      return pu.GetMyObject();
  }

}

You dont need a JSON serializer, tagging it with the ScriptService attribute gives it tie ability to serialize JSON out. You were pre serializing the JSON and then serializing it again :(

回答2:

Why are you calling JavaScriptConvert.SerializeObject?

Can't you just change the return type of your method to be the type returned by pu.getMyObject() and the framework will do the rest?

In other words...

[WebMethod (Description="doc here")]    
[ScriptMethod(ResponseFormat=ResponseFormat.Json)]     
public MyObjectType responseMyObject() 
{
    Proxy pu = new Proxy(...);

    ...

    return pu.GetMyObject();
}

At the moment I think you're serializing your object into a JSON format and then, when you return from the method, the framework is serializing that string (which contains JASON formatted data) into a JSON format.