ASPxCardView - How to implement custom date validation in Batch Edit mode

This example illustrates how to implement custom date validation in Batch Edit mode:
1) The ASPxClientCardView.BatchEditCardValidating event is used to check values on the client.
2) The ASPxCardView.CardValidating event is used to check values on the server.
3) The CardViewBatchEditSettings.AllowValidationOnEndEdit property allows switching between validation modes on the client side. 

If the variation between the HireDate and BirthDate columns is less than 18, input data is considered invalid and data update is not allowed.