Returning JSON from ASMX, and handling it correctly in Javascript

Question

I realize there are tonnes of similar questions already up here but I cannot figure this one out.

I have a Web Service (C#, .net 3.5). The essential Code you need

Answer 1

Yes, definitely do not manually serialize the object. If you return a Member type, the framework will handle the JSON serialization for you.

When you're seeing the [object XMLHttpRequest] alert, that sounds like it's getting into the error handler in your $.ajax() call, where the response passes in its XHR object as the first parameter. You're probably getting a 500 error on the server.

Here's an example of decoding the ASP.NET AJAX error response in jQuery. Most simply, change your error handler to this:

error: function(xhr, status, error) {
  var err = eval("(" + xhr.responseText + ")");

  alert(err.Message);
}

That will give you some insight into what the specific error is.