Using Data Annotations To Perform Validations

Validations are very important to limit user input. So, we need to validate our form client side and server side as well. Developers write the validations through if/else statements again and again to check the data and then they go through the exceptions, this is the way developers normally apply the validations on the forms.

source https://www.c-sharpcorner.com/article/using-data-annotations-to-perform-validations/