Add Textboxes To Gridview Cell On Edit Select?

I could really use some help on this. I have been searching for a solution on the web but haven't been able to find much help.I need to add textboxes to a gridview edit cell, based on the number of rows of text in one of the cells. I have coded the capture of the number of textboxes I need to add.

But I am not sure which Gridview event to add the code, when going into edit mode, to run the loop that will insert additional Textboxes in a specific column of the row selected to edit.

The user sees colA that has text with line vbCRLF's embedded say:

"This is sample text."

"Line2"

"Line3"

My code reads three Carriage Return, Line feeds. So when the user goes into Edit mode I want to provide one text box for each line or more accurately, add two more as one will already exist.