adding public void function in public datatable function

hello guys, i dont have any idea what subject should i put, but i have a problem how
i want to add my function in datatable since my delete button in gridview area.
here part of my error
public void actvt()
{
     process.....
}
 
public datatable (string userID)
{
      actvt();
}
 
my actvt function cant be read at datatable
any idea how to make it run in datatable..
TQVM