How to trace errors in asp.net core

Question

I noticed that when you create a default asp.net core project in visual studio, there is an Error action that looks like this:

    public IActionResult Error()
    {
        ViewData["RequestId"] = Activity.Current?.Id ?? HttpContext.TraceIdentifier;
        return View();
    }

The error page shows that RequestId properly, however, I don't know how to check the details of that error if my user sends me a screenshot of that error. Where is this stored?

Answer 1

ExceptionHandlerMiddleware stores the exception in HttpContext as an ExceptionHandlerFeature.

So in the Error Action you can get the error message by doing something like this,

public IActionResult Error()
{
    var ehf = HttpContext.Features.Get<IExceptionHandlerFeature>();
    ViewData["ErrorMessage"] = ehf.Error.Message;

    return View();
}