Handling exception in asp.net core?

You can use to handle exceptions UseExceptionHandler(), put this code in your
Startup.cs.

UseExceptionHandler can be used to handle exceptions globally. You can get all the details of exception object like Stack Trace, Inner exception and others. And then you can show them on screen. Here

Here You can read more about this diagnostic middleware and find how using IExceptionFilter and by creating your own custom exception handler.

   app.UseExceptionHandler(
                options =>
                {
                    options.Run(
                        async context =>
                        {
                            context.Response.StatusCode = (int) HttpStatusCode.InternalServerError;
                            context.Response.ContentType = "text/html";
                            var ex = context.Features.Get<IExceptionHandlerFeature>();
                            if (ex != null)
                            {
                                var err = $"<h1>Error: {ex.Error.Message}</h1>{ex.Error.StackTrace}";
                                await context.Response.WriteAsync(err).ConfigureAwait(false);
                            }
                        });
                }
            );

You have to also delete default setting like UseDeveloperExceptionPage(), if you use it, it always show default error page.

   if (env.IsDevelopment())
        {
            //This line should be deleted
            app.UseDeveloperExceptionPage();
            app.UseBrowserLink();
        }
        else
        {
            app.UseExceptionHandler("/Home/Error");
        }