Suppose you have a registration form with textboxes to hold a StudentId and a CourseId. Also provided is a button which opens a second form which allows you to lookup a StudentId using by their first or last name.
How return the StudentId from the search form, and load it into the StudentId textbox on the registration form?
I think this answer explains the solution nicely.
Basically, you create a new constructor for your search form which takes a form object as a parameter. When you create call your search form, you pass a reference to the registration form with it.
When the search form finds the studentId, it uses this reference to the registration form to call a public method in the registration form which populates the studentId textbox.
