前一篇文章讲到非队列消息会直接把消息Dispatch到窗口函数上，窗口函数长什么样？
//就是一个大case分支
//要想拦截消息，override窗口函数是一个办法！
procedure TCustomForm.WndProc(var Message: TMessage);
var
FocusHandle: HWND;
SaveIndex: Integer;
MenuItem: TMenuItem;
Canvas: TCanvas;
DC: HDC;
begin
with Message do
case Msg of
WM_ACTIVATE, WM_SETFOCUS, WM_KILLFOCUS:
begin
end;
CM_EXIT:
if HostDockSite <> nil then DeActivate;
end;
end;
假如我们要用这种方法拦截Edit的Copy,Cut消息怎么办？
难道我们还要继承CustomEdit,再override窗口函数，生成新的MyEdit?有人想，直接用一个函数先把CustomEdit的WndProc替换掉不就行了，使用完毕后，再还原！
//替换窗口函数
TForm1 = class(TForm)
edt1: TEdit;
btn1: TButton;
procedure FormCreate(Sender: TObject);
procedure FormDestroy(Sender: TObject);
private
FOldWndProc: TWndMethod; { Private declarations }
public
{ Public declarations }
procedure NewWndProc(var Message: TMessage); end; var
Form1: TForm1; implementation {$R *.dfm} procedure TForm1.NewWndProc(var Message: TMessage);
begin
if (Message.Msg <> WM_CUT) and (Message.Msg <> WM_COPY) and
(Message.Msg <> WM_PASTE) then
FOldWndProc(Message);
end; procedure TForm1.FormCreate(Sender: TObject);
begin
FOldWndProc := edt1.WindowProc;
edt1.WindowProc := NewWndProc; end; procedure TForm1.FormDestroy(Sender: TObject);
begin
edt1.WindowProc := FOldWndProc;
end;
end.