Get error message if ModelState.IsValid fails?

Question

I have this function in my controller.

[HttpPost]
public ActionResult Edit(EmployeesViewModel viewModel)
{
    Employee employee = GetEmployee(viewModel.Empl         


        

Answer 1

If you're looking to generate a single error message string that contains the ModelState error messages you can use SelectMany to flatten the errors into a single list:

if (!ModelState.IsValid)
{
    var message = string.Join(" | ", ModelState.Values
        .SelectMany(v => v.Errors)
        .Select(e => e.ErrorMessage));
    return new HttpStatusCodeResult(HttpStatusCode.BadRequest, message);
}