eg ModelState.Try("model.Email", () => user.ChangeEmail(newEmail));

gistfile1.cs

// credit: @mcintyre321
public static class ModelStateDictionaryExtensions
{
    public static bool Try(this ModelStateDictionary ms, string key, Action action)
    {
        try
        {
            action();
            return true;
        }
        catch (Exception ex)
        {
            ms.AddModelError(key, ex);
            return false;
        }
    }
}