I have an action :
[HttpPost]
public ActionResult MyAction(MyModel model)
{
...
if (model.MyCondition == true)
throw new Exception("MyMessage);
....
}
I'd like get the message "MyMessage" on the Ajax side :
onSuccess: function () {
...
},
onError: function (jqXHR, textStatus, errorThrown) {
//I'd like get "MyMessage" here
}
An idea how to do this ? When I check with the debugger I don't see my string.
Implementing an error attribute is a good way. Also, I usually don't throw the exception, but return a status code according to error. You can write to your response stream and access in js via XMLHttpRequest.responseText :
if (model.MyCondition == true)
{
if (Request.IsAjaxRequest())
{
Response.StatusCode = 406; // Or any other proper status code.
Response.Write("Custom error message");
return null;
}
}
and in js:
...
error: function (xhr, ajaxOptions, errorThrown) {
alert(xhr.responseText);
}
Try returning a ContentResult from your Action with a GET type action.
[HttpGet]
public ContentResult MyAction(String variablename)
{
...
if (some_verification == true)
return Content("MyMessage);
....
}
On your view page,
$.ajax({
url: 'your controller/action url',
type: 'get',
cache: false,
async: false,
data: { variablename: "value" },
success: function (data) {
alert(data);
},
error: function () {
alert('Error doing some work.');
}
});
A possibility could be to create a BaseController class where you override the Controller's OnException(ExceptionContext filterContext) method and convert the exceptions into JSON for being able to easily process them from a JavaScript client.
I've solved this implementing a custom ErrorAttribute:
[NonAction]
protected void OnException(ExceptionContext filterContext)
{
this.Session["ErrorException"] = filterContext.Exception;
if (filterContext.Exception.GetType() == typeof(MyException))
{
// Mark exception as handled
filterContext.ExceptionHandled = true;
// ... logging, etc
if (Request.IsAjaxRequest())
{
/* Put your JSON format of the result */
filterContext.Result = Json(filterContext.Exception.Message);
}
else
{
// Redirect
filterContext.Result = this.RedirectToAction("TechnicalError", "Errors");
}
}
}
and then decorating my actions with it.
You can also override the OnException method of your controller, but I think that the custom attribute is way more flexible.
