Question on Comparing Data

Question

I am new to vb.net. I have created a form using vb.net. The form has the following fields and a Datagrid: a. Revision b. Installation c. Part No d. Qty e. Description f. Change Rev (Field is Disable - autofill based on criteria) The form also has the command buttons: Save and Close For initial revision "-", I am able to capture and saved what was key-in the above fields (except "Change Rev"). For making subsequent revision, "A" (for example), the previous revision data is recaptured onto the fields. However, I have a problem. Is it possible when there is any changes made to any of the following field (Part No, Qty and Description) that is different from the previous revision, the field "Change Rev" will auto-fill the current revision "A" in Change Rev. The purpose is to tell the user which set of data is change and in what revision, if there is no change make to data, the Change Rev remain as "". Any advise how to approach the above is appreciated. Thanks