unit HookMain; interface uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
StdCtrls, ExtCtrls; type
THookForm = class(TForm)
SendBtn: TButton;
GroupBox1: TGroupBox;
LogList: TListBox;
DoLog: TCheckBox;
ExitBtn: TButton;
Button1: TButton;
procedure SendBtnClick(Sender: TObject);
procedure FormCreate(Sender: TObject);
procedure FormDestroy(Sender: TObject);
procedure ExitBtnClick(Sender: TObject);
procedure Button1Click(Sender: TObject);
private
function AppWindowHook(var Message: TMessage): Boolean;
end; var
HookForm: THookForm; implementation {$R *.DFM} procedure THookForm.FormCreate(Sender: TObject);
begin
Application.HookMainWindow(AppWindowHook);
end; procedure THookForm.FormDestroy(Sender: TObject);
begin
Application.UnhookMainWindow(AppWindowHook);
end; function THookForm.AppWindowHook(var Message: TMessage): Boolean;
const
LogStr = 'Message ID: $%x, WParam: $%x, LParam: $%x';
begin
Result := True;
if DoLog.Checked then
with Message do
LogList.Items.Add(Format(LogStr, [Msg, WParam, LParam]));
end; procedure THookForm.SendBtnClick(Sender: TObject);
begin
SendMessage(Application.Handle, WM_NULL, , );
end; procedure THookForm.ExitBtnClick(Sender: TObject);
begin
Close;
end; procedure THookForm.Button1Click(Sender: TObject);
begin
ShowMessage('ddd');
end; end.
理论解释：
Enables a native Windows dialog box to receive messages sent to the application's main window.
Use HookMainWindow to ensure that a native Windows dialog box behaves correctly as a child of the application, not as a stand-alone window. For example, switching among applications with Alt+Tab treats the application as a single task after calling HookMainWindow, rather than treating the native Windows dialog box as a separate task.
When the window identified by the Handle property receives relevant dialog messages, it passes them to the dialog procedure passed as the Hook parameter.
There is no problem with leaving a dialog box hooked into the main window, even for extended periods. However, should the dialog box close, call the UnhookMainWindow method to release the hook.