In my case, if I remove the the contentType, I get the Internal Server Error.
This is what I got working after multiple attempts:
var request = $.ajax({
type: 'POST',
url: '/ControllerName/ActionName' ,
contentType: 'application/json; charset=utf-8',
data: JSON.stringify({ projId: 1, userId:1 }), //hard-coded value used for simplicity
dataType: 'json'
});
request.done(function(msg) {
alert(msg);
});
request.fail(function (jqXHR, textStatus, errorThrown) {
alert("Request failed: " + jqXHR.responseStart +"-" + textStatus + "-" + errorThrown);
});
And this is the controller code:
public JsonResult ActionName(int projId, int userId)
{
var obj = new ClassName();
var result = obj.MethodName(projId, userId); // variable used for readability
return Json(result, JsonRequestBehavior.AllowGet);
}
Please note, the case of ASP.NET is little different, we have to apply JSON.stringify() to the data as mentioned in the update of this answer.