ASP.NET Core MVC Interview Question #140

How should 404 errors be handled in MVC?

Dependency Injection, Services, Error Handling, Logging & Performance Senior Advanced

Quick Interview Answer

A controller can return NotFound when a requested resource does not exist. The application may also configure status-code pages so unmatched routes and other 404 responses display a consistent user-facing page.

Detailed Explanation

A missing business record should be distinguished from a server error. Returning an accurate 404 improves HTTP semantics, diagnostics, and search-engine behavior.

Code Example

public async Task<IActionResult> Details(int id)
{
    var product = await _service.GetAsync(id);

    if (product == null)
        return NotFound();

    return View(product);
}