Delphi/Lazarus: Select all with CTRL+A in ListView

If you have written an application in Delphi or Lazarus containing a TListView with some entries, it is quite nice to have the possibility to select all items of the ListView by pressing the key shortcut CTRL and A on the keyboard. Unfortunately, the ListView does not support this automatically.

But we can quickly remedy this by writing the following code in the OnKeyDown event of our ListView:

procedure Tprog.ListView1KeyDown(Sender: TObject; var Key: Word; 
Shift: TShiftState);
var
  i: integer;
begin
  if (Shift = [ssCtrl]) and (key = ord('A')) then begin
     ListView1.Items.BeginUpdate;
     for i := 0 to ListView1.Items.Count-1 do Items[i].Selected:=true;
     ListView1.Items.EndUpdate;
  end;
end;

First of all, this code checks which keys have been pressed. If the keys are "CTRL" (Shift = [ssCtrl]) and "A", we go through all entries of the ListView and set "Selected" to "true". Of course, you can still add conditions for other keys or key combinations.

Important: To be able to select multiple items in the ListView at all, we have to set the property "MultiSelect" of our ListView to "true" before.