Delphi remap key to multi characters

Question

I want that when I press a M or m character, 000000 gets input on a specific TEdit box:

procedure Tfrm.FormKeyPress(Sender: TObject; var Key: Char) ;
var
  i : integer;
begin
  if Key in ['m'] + ['M'] then Key := '0';
end;

With this code, I can just remap 'M' key to single character. How can I remap 'M' to multiple characters for a TEdit box?

Answer 1

Use the OnKeyPress event of the TEdit itself, not the OnKeyPress event of the parent TForm. Set the Key parameter to #0 to swallow it, and then insert 6 individual '0' characters into the TEdit:

procedure Tfrm.Edit1KeyPress(Sender: TObject; var Key: Char);
var
  i : integer;
begin
  if Key in ['m', 'M'] then
  begin
    Key := #0;
    for I := 1 to 6 do
      Edit1.Perform(WM_CHAR, Ord('0'), $80000001);
  end;
end;

Alternatively:

procedure Tfrm.Edit1KeyPress(Sender: TObject; var Key: Char);
begin
  if Key in ['m', 'M'] then
  begin
    Key := #0;
    Edit1.SelText := '000000';
  end;
end;