ModelState.AddModelError to show up.<span asp-validation-for="Foo"></span> for each input, as well as a <div asp-validation-summary="All"></div>.span and the div ModelState, the custom error message will only show up in the div, not in the <span>.<div asp-validation-summary="ModelOnly"></div>, then the manually added error stops showing there as well. This makes me suspect I'm adding the error wrong, but there's not a lot of room for variation. Any ideas on what I'm doing wrong? Thanks for taking the time to read/answer.
