Automatically allowing Ctrl+A to select all in a TMemo? - delphi

Question

In Delphi 7's TMemo control, an attempt to do the key combo Ctrl + A to select all does not do anything (doesn't select all). So I've made this procedure:
procedure TForm1.Memo1KeyDown(Sender: TObject; var Key: Word;
Shift: TShiftState);
var
C: String;
begin
if ssCtrl in Shift then begin
C:= LowerCase(Char(Key));
if C = 'a' then begin
Memo1.SelectAll;
end;
end;
end;
Is there a trick so that I don't have to do this procedure? And if not, then does this procedure look OK?

Answer 1

This is more elegant:
procedure TForm1.Memo1KeyPress(Sender: TObject; var Key: Char);
begin
if Key = ^A then
begin
(Sender as TMemo).SelectAll;
Key := #0;
end;
end;

Answer 2

While the accepted answer by Andreas Rejbrand is correct, it is not the expected Windows visual behavior. It leaves the cursor position unchanged. Ctrl-A (Select All) should leave the cursor at the bottom of the text and scroll the control so the cursor is in view.
If this is not done, the control exhibits odd behavior. For example, assume there is more text than fits the window, and the window is not scrolled to the bottom. You press Ctrl-A, and all text is Selected. Ctrl-C will now copy all text to the clipboard. Although you can't see it the cursor is now at the bottom of the View, which has not scrolled. If you now press Ctrl-Down the Selected Text becomes just the text in view, then the cursor moves down and window scrolls down one line. The new bottom line is not selected. This makes it look like the Select All only selected the visible text.
The fix is simply to move the caret to the end of text before SelectAll.
procedure TForm1.Memo1KeyPress(Sender: TObject; var Key: Char);
begin
if Key = ^A then begin
With Sender as TMemo do begin
SelStart := Length(Text);
Perform(EM_SCROLLCARET, 0, 0);
SelectAll;
end;
Key := #0; //Eat the key to suppress the beep
end;
end;
Note that 'Eat the key' only works in the OnKeyPress event, not the OnKeyDown or OnKeyUp events.

Answer 3

I used the previous answer and discussion to create a standalone component which handles the KeyPress event which I use in small test programs.
TSelectMemo = class(TMemo)
protected
procedure KeyPress(var Key: Char); override;
end;
...
procedure TSelectMemo.KeyPress(var Key: Char);
begin
inherited;
if Key = ^A then
SelectAll;
end;
Another way of adding "select all" behavior to all components on a form is to add an action list to your form with a standard select all action.