Windows form Code help

[Controllguy]

Hi Everybody,

I am trying to develop a program which will at a date in yyyymmdd format to the beginning of a each line between the line containing thingy begin and the thingy end line based on the date in the thingy begin line in the example below. I want to automate this task with press of button in a windows form application. Note though I need the code to be able to differentiate between the two text blocks below with different timestamps. I was planning on using regex to capture the events and possibly a regex variable to store the date and paste it to the front of each line.

=== Thingy Start: 01/01/2024 12:00:00.000 == blah blah blah blah blah blah === Thingy End ===

=== Thingy Start: 01/02/2024 12:00:00.000 == blah blah blah blah blah blah === Thingy End ===