Application.HookMainWindow(AppHook)(zt)-优快云博客

本文介绍了一种在Delphi中通过自定义消息处理函数AppHook来尝试拦截窗口还原(SC_RESTORE)消息的方法。但该方法无法成功拦截WM_SYSCOMMAND消息中的SC_RESTORE操作，即使使用了重载WndProc或自定义消息处理也无法实现。

type
TMainForm = class(TForm)
    procedure FormCreate(Sender: TObject) ;
    procedure FormDestroy(Sender: TObject) ;
private
    function AppHook(var msg: TMessage): boolean;
end;

implementation

procedure TMainForm.FormCreate(Sender: TObject) ;
begin
Application.HookMainWindow(AppHook) ;
end;

function TMainForm.AppHook(var msg: TMessage): boolean;
begin
result := false;
if (msg.Msg = WM_SYSCOMMAND) and (msg.WParam = SC_RESTORE) then
    result := MessageDlg('Are you an Admin?', mtWarning, mbYesNo, 0) = mrNo;
end;

procedure TMainForm.FormDestroy(Sender: TObject) ;
begin
Application.UnhookMainWindow(AppHook) ;
end;
type
TMainForm = class(TForm)
    procedure FormCreate(Sender: TObject) ;
    procedure FormDestroy(Sender: TObject) ;
private
    function AppHook(var msg: TMessage): boolean;
end;

implementation

procedure TMainForm.FormCreate(Sender: TObject) ;
begin
Application.HookMainWindow(AppHook) ;
end;

function TMainForm.AppHook(var msg: TMessage): boolean;
begin
result := false;
if (msg.Msg = WM_SYSCOMMAND) and (msg.WParam = SC_RESTORE) then
result := MessageDlg('Are you an Admin?', mtWarning, mbYesNo, 0) = mrNo;
end;

procedure TMainForm.FormDestroy(Sender: TObject) ;
begin
Application.UnhookMainWindow(AppHook) ;
end;

重载WndProc不能截取SC_RESTORE，用自定义消息(WM_SYSCOMMAND)也不能截取。