k12 MVC approach form required field validation

Depending on where you are in Kentico this could change. If you're on a Form, Page Type, Custom Table, or Module Class you can use the form controls validation settings on the field.

For instance if you have a text field for a first name on a page types, you select the textbox form control for the field, then scroll down a little to the validation section and enter in your custom validation message or even enter in your custom validation rule.

For DancingGoat Application example is as below.

You can go to the page type you had created (In my case it's Article page type). Then select the field you want to validate (I has selected "ArticleTitle"). And scroll down to the validation or click on validation link bellow the all fields. Then on the "Default error message" type your message before doing this this field is marked as the Required field by just clicking on the required checkbox. You can also add the validation rule over there by "Validation rules" fields "Add validation rule" button. There you go and you can display the validation message as per your requirement.

Note that the validation rules are not applied to an empty field. This seems counter intuitive to me. If my validation rule on a textbox is "min length of 2", the rule is NOT applied unless a value is entered in the box. Please fix Kentico 12 MVC to render the validation error message for empty fields as well. This would allow the error message to be consistent for empty and non-empty validation cases.