Best Practices: Passing values between forms

[Job Lot]

I have a form “Form1�, which shows records from database. Now if user wants
to change the records, they have to click a button which opens another form
“Form2� where they can actually make amendments. Now I want to validate the
date on click of OK button on form2 and if there are any errors set the focus
back to form2 until user provides valid data, else show the amended vales
from form2 on to form1. Also, if user click “Cancel� on form2, it should
change values on form1.

Could someone please tell me what would be the best way to implement this
scenario. I want to show forms as modal. I am totally baffled how to pass
values between two form, how should I open and close form2. Should I set
DialogResult property of button controls, should I use close method, when
should I use Dispose. when to use Dispose, etc etc… I am really confused
about navigation between two form. Please set me in right direction. I having
heaps of debugging problems cause of it as well.