c# - MVC .Net Core Model Validation - The value '' is invalid. Error -

i trying use model validation in mvc .net core , can't manage replace default error message 'the value '' invalid'.

in theory, can replace our own custom error message using errormessage annotation in model. couldn't find way make 1 work.

my model

[required(errormessage = "date required")] [datatype(datatype.date, errormessage = "invalid date format")]                 [display(name = "appointment date")] [displayformat(dataformatstring = "{0:dd/mm/yyyy}", applyformatineditmode = true)] public datetime appointmentdate { get; set; } 

i put different errormessage both required , datatype tag shown in above.

my html view

    <div class="col-md-2">         <input class="form-control" asp-for="appointmentdate">         <span asp-validation-for="appointmentdate" class="text-danger"></span>     </div> 

could please me how error message replaced? thanks.

in order make required attribute works need make field nullable:

public datetime? appointmentdate { get; set; } 

edit: note datatype attribute doesn't perform validation on field. mvc validate date when applying binding post data model