Displaying all application errors in a view

Question

I'm learning ASP.NET Core with MVC pattern and I didn't find anything useful related to this argument.

Actually I'm looking for a way to handle all the application errors inside a single View. The first thing that I did was create the View for display the error, this is the design (pretty simple though):

<h2>@(ViewBag.ErrorMessage == null ? "An error happened" : "" + @ViewBag.ErrorMessage + "")</h2>

and this is the Error controller:

public class ErrorController : Controller
{
 [HttpGet]
 public IActionResult Index(string errorMessage)
 {
 ViewBag.ErrorMessage = errorMessage;
 return View();
 }
}

Essentially, I used the ViewBag for valorize a property called ErrorMessage which contains the parameter errorMessage.

Let me show an example of this logic for the email confirmation:

public async Task<IActionResult> ConfirmEmail(string userId, string token)
{
 if (userId == null || token == null)
 {
 return RedirectToAction("Index", "Error");
 }
 var user = await _userManager.FindByIdAsync(userId);
 if (user != null)
 {
 if (user.EmailConfirmed)
 { 
 return RedirectToAction("Index", "Error", new { errorMessage = "Email already confirmed" });
 }
 IdentityResult result;
 try
 {
 result = await _userManager.ConfirmEmailAsync(user, token);
 }
 catch (InvalidOperationException ex)
 {
 return RedirectToAction("Index", "Error", new { errorMessage = ex.Message });
 }
 if (result.Succeeded)
 {
 //TODO: Send another email
 return View("ConfirmEmail", user);
 }
 }
 return RedirectToAction("Index", "Error", new { errorMessage = "Utser not found" });
 }

Now, I'm not an expert yet of ASP.NET Core so I don't know if my practice is good enough for a production environment, someone could maybe propose a better way or improve my solution?

Answer 1

While I see no problem design-like or code-like, in the point of view of the user, It can be frustrating.

I guess the method ConfirmEmail is called from a form.

So, imagine how frustrating it is if you fill a form and if there is any error in this form, it redirects you to the Error View ?

Imo, Error display should be handled by Javascript/Html/Css on the same page which thrown the error to avoid losing any data from user's pov. Like, displaying a notification or even an error message below the field.

How you display the error should be specific of the error.