IDM 4.01

I have a 2 column pick list on the requestor's form. They choose items
and submit for approval.

The approver can only remove items. The source of data for the picklist
is a mapping table. I have the code working if 1 or more items are
selected. The issue I have is if no items are selected the form is
unable to evaluate.

What is the best way to terminate a preactivity data mapping?

if(flowdata.getdata == null){
//This part does not
populate picklist
//This part works

Thank you