Custom validation

[n/a]

Hi,

What is the method for defining custom validation in a Form?  For example, in the Kendo UI for jQuery Form validation demo (https://demos.telerik.com/kendo-ui/form/validation) there is custom validation performed on the RetireDate to ensure that it's after the HireDate. However, the ASP.NET Core validation demo (https://demos.telerik.com/aspnet-core/form/validation)  contains no such validation.  Would it be possible to provide an example on how to perform this validation using ASP.NET Core?

Thanks,
Scott

[Ivan Danchev]

Hello Scott,

The ASP.NET Core Form does not have the validation configuration of the jQuery Form. Custom validation in the Core Form can be done on the server. In the Validation demo, both LastName and RetireDate are validated in the "Validation" action:

[HttpPost]
public ActionResult Validation(UserViewModel model)
{
    int compareDates = Nullable.Compare<DateTime>(model.HireDate, model.RetireDate);

    if (model.FirstName == model.LastName)
    {
        ModelState.AddModelError("LastName", "LastName must be different than First Name.");
    }
    else if (compareDates >= 0)
    {
        ModelState.AddModelError("RetireDate", "Retire Date must be after Hire Date.");
    }

    if (!ModelState.IsValid)
    {
        return View(model);
    }
    else
    {
        TempData["View"] = "Validation";
        return View("Success");
    }
}

The logic used the demo's view and controller can be seen by selecting the "View Source" tab in the demo.

Regards,
Ivan Danchev
Progress Telerik