jQuery Ajax error handling, show custom exception messages

Question

Is there some way I can show custom exception messages as an alert in my jQuery AJAX error message?

For example, if I want to throw an exception on the server side v

Answer 1

Throw a new exception on server using:

Response.StatusCode = 500

Response.StatusDescription = ex.Message()

I believe that the StatusDescription is returned to the Ajax call...

Example:

        Try

            Dim file As String = Request.QueryString("file")

            If String.IsNullOrEmpty(file) Then Throw New Exception("File does not exist")

            Dim sTmpFolder As String = "Temp\" & Session.SessionID.ToString()

            sTmpFolder = IO.Path.Combine(Request.PhysicalApplicationPath(), sTmpFolder)

            file = IO.Path.Combine(sTmpFolder, file)

            If IO.File.Exists(file) Then

                IO.File.Delete(file)

            End If

        Catch ex As Exception

            Response.StatusCode = 500

            Response.StatusDescription = ex.Message()

        End Try

Answer 2

You have a JSON object of the exception thrown, in the xhr object. Just use

alert(xhr.responseJSON.Message);

The JSON object expose two other properties: 'ExceptionType' and 'StackTrace'

Answer 3

 error:function (xhr, ajaxOptions, thrownError) {
        alert(xhr.status);
        alert(thrownError);
      }

in code error ajax request for catch error connect between client to server if you want show error message of your application send in success scope

such as

success: function(data){
   //   data is object  send  form server 
   //   property of data 
   //   status  type boolean 
   //   msg     type string
   //   result  type string
  if(data.status){ // true  not error 
         $('#api_text').val(data.result);
  }
  else 
  {
      $('#error_text').val(data.msg);
  }

}

Answer 4

This is probably caused by the JSON field names not having quotation marks.

Change the JSON structure from:

{welcome:"Welcome"}

to:

{"welcome":"Welcome"}

Answer 5

Controller:

public class ClientErrorHandler : FilterAttribute, IExceptionFilter
{
    public void OnException(ExceptionContext filterContext)
    {
        var response = filterContext.RequestContext.HttpContext.Response;
        response.Write(filterContext.Exception.Message);
        response.ContentType = MediaTypeNames.Text.Plain;
        filterContext.ExceptionHandled = true;
    }
}

[ClientErrorHandler]
public class SomeController : Controller
{
    [HttpPost]
    public ActionResult SomeAction()
    {
        throw new Exception("Error message");
    }
}

View script:

$.ajax({
    type: "post", url: "/SomeController/SomeAction",
    success: function (data, text) {
        //...
    },
    error: function (request, status, error) {
        alert(request.responseText);
    }
});

Answer 6

I believe the Ajax response handler uses the HTTP status code to check if there was an error.

So if you just throw a Java exception on your server side code but then the HTTP response doesn't have a 500 status code jQuery (or in this case probably the XMLHttpRequest object) will just assume that everything was fine.

I'm saying this because I had a similar problem in ASP.NET where I was throwing something like a ArgumentException("Don't know what to do...") but the error handler wasn't firing.

I then set the Response.StatusCode to either 500 or 200 whether I had an error or not.