SelectAll for a ListBox Column

In a Contextual Menu, I want to Select All, but based on a Column (instead of Row):

a. the idea was nice at coding time (around 4:00 earlier today), but what use can it be ?

b. I know how to Select a Row (or a set of Rows, continguous or not, eventually based on text inside a Cell), but I do not have an idea on how to select Cells.

Nota: I implemented the code to add the MenuItem and to execute the code (commented), in the can.

TIA

something like that? download

Yes ! Something like that, THANK YOU.