C# .WithJson Invalid JSON Error

Question

I'm trying to build this JSon string as follows

push.QueueNotification(new GcmNotification().ForDeviceRegistrationId(RegID)
                                  .WithJson(@"{""message"":"+Message+"}"));

Now whenever I run this, I get the InvalidCastException was unhandled/Invalid JSON detected! error message.

However when I do the following

push.QueueNotification(new GcmNotification().ForDeviceRegistrationId(RegID)
                                  .WithJson(@"{""message"":""Hello World""}"));

It works perfectly fine.

If anyone has any ideas or suggestions on how to get this working it would be greatly appreciated.

Thanks!

Answer 1

Since you're manually constructing your JSON (which you shouldn't do, really), you have to ensure Message contains the proper formatting for the portion of the JSON it contains.

string Message = "Hello World";

will result in JSON that doesn't include quotes around a string, which is invalid. Ie:

{ "message" : Hello World }

You could add quotes manually, but what you should do is use a JSON library. .NET has a simple one in JavaScriptSerializer. With it you can do something like this and never worry about whether your Message contains the proper formatting.

var obj = new { message = "Hello World" };
var serializer = new JavaScriptSerializer();
var json = serializer.Serialize(obj);

push.QueueNotification(new GcmNotification().ForDeviceRegistrationId(RegID)
                                            .WithJson(json));