public async Task <IActionResult> OnPostAsync() { if (!ModelState.IsValid) { return(Page()); } _repository.UpdateAsync(CommonExample); try { await _repository.SaveChangesAsync(); } catch (DbUpdateConcurrencyException) { if (!_repository.CommonExampleExists(CommonExample.Id)) { return(NotFound()); } else { throw; } } return(RedirectToPage("./Index")); }