Adding validation logic
Data validation in interfaces is important and can go way beyond making a field mandatory. I will show you how to implement the following validations:
- A selected date must be in the future.
- An entered number must be in a specific range.
An important aspect is that Appian only executes validations if the field has any value. So, you cannot implement a validation that checks for an empty field. Set the required parameter to true to do that. Validations can then check any entered values. Make the required parameter false to create an optional field that can still have validations.
While I use a simple literal in the examples, it is a good idea to store values such as thresholds or range definitions in constants. This way these values can be reused and use the Update Constant smart service in a process model to let a user modify values stored in constants.
Date validation
Use a simple if() statement to check whether the entered value...
