With the change in UI for Business Rules in Dynamics 365, which was supposed to be a simpler UI and visually appealing seems to lag intuitiveness as it takes couple to tries to understand how to work with it.
- In given example I am having an entity for Absence Calendar for users.
- I have start date and end date for users. Validation is that End Date should be >= start date.
- Go to your solution -> expand the entity -> click on business rules -> click new
Key in the Business Rule Name
Click on Condition Box and on right side under properties you will see UI to update condition.
Update the rule condition and click apply.
Click on Add -> Add Show Error Message. It will display plus sign near condition success and failure. Click on the + sign near positive condition
On right hand select the field where the error message should display. Key in the error message and click apply.
- Now Save -> Activate the Business Rule.