Populating Values when a page loads

Summary

Populating Values when a page loads

Content

Is there a way of calling custom code to populate fields on a screen when the form loads?

I have a search screen which returns items and then when the user selects one they move to the next screen which we want some fields pre-populated with data based on the item selected in the previous screen.

I have been able to add a button to the new screen which when clicked fills in the fields as required but we want the fields filled in when the form loads.

Thank

Shane