RichEdit 中拦截 TAB 键

这里有很多类似的问题，但我找不到我的问题的答案。

I have a TRichEdit and want to implement some custom behaviour when the user presses Tab. I set the rich edit's WantTabs property to True and tried to add my custom behaviour in OnKeyDown, which works fine, but unfortunately after that the "normal" tab behaviour is executed as well (inserting a tab character in the edit). I tried setting Key to 0 in the event handler but that doesn't help.

如何防止执行“正常”选项卡行为？

Use the OnKeyPress事件代替：

procedure TForm1.RichEdit1KeyPress(Sender: TObject; var Key: Char);
begin
  if Key = chr(VK_TAB) then
  begin
    beep;
    Key := #0;
  end;
end;

或者，如果您确实需要使用OnKeyDown事件，只需删除关键消息：

procedure TForm1.RichEdit1KeyDown(Sender: TObject; var Key: Word;
  Shift: TShiftState);
var
  msg: TMsg;
begin
  if Key = VK_TAB then
  begin
    beep;
    while PeekMessage(msg, RichEdit1.Handle, WM_KEYFIRST, WM_KEYLAST,
      PM_REMOVE) do;
  end;
end;