学习 Message(5): 关于 TApplicationEvents.OnMessage 的第二个参数 可以屏蔽 TWebBrowser右键菜单:

http://www.cnblogs.com/del/archive/2008/10/25/1319318.html

TApplicationEvents.OnMessage 的第二个参数 Handled 如果是 True, 表示消息已经处理过了, 到此为止.

unit Unit1;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, AppEvnts, StdCtrls;

type
TForm1 = class(TForm)
Memo1: TMemo;
ApplicationEvents1: TApplicationEvents;
procedure ApplicationEvents1Message(var Msg: tagMSG; var Handled: Boolean);
procedure FormMouseDown(Sender: TObject; Button: TMouseButton;
Shift: TShiftState; X, Y: Integer);
end;

var
Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.ApplicationEvents1Message(var Msg: tagMSG;
var Handled: Boolean);
begin
if Msg.message = WM_LBUTTONDOWN then
begin
Memo1.Lines.Add('OnMessage');
Handled := False; {Handled 默认是 False, 这句可以省略}
//    Handled := True;  {如果这样, 下面 OnMouseDown 事件将不会得到执行}
end;
end;

procedure TForm1.FormMouseDown(Sender: TObject; Button: TMouseButton;
Shift: TShiftState; X, Y: Integer);
begin
Memo1.Lines.Add('OnMouseDown');
end;

end.

我们可以利用这个特性来屏蔽一些消息, 譬如给 TWebBrowser 屏蔽右键菜单:

unit Unit1;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, OleCtrls, SHDocVw, AppEvnts;

type
TForm1 = class(TForm)
WebBrowser1: TWebBrowser;
ApplicationEvents1: TApplicationEvents;
procedure FormCreate(Sender: TObject);
procedure ApplicationEvents1Message(var Msg: tagMSG; var Handled: Boolean);
end;

var
Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.ApplicationEvents1Message(var Msg: tagMSG;
var Handled: Boolean);
begin
if IsChild(WebBrowser1.Handle, Msg.hwnd) and (Msg.message = WM_RBUTTONDOWN) then
begin
Handled := True;
end;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
WindowState := wsMaximized;
WebBrowser1.Align := alTop;
WebBrowser1.Navigate('http://www.cnblogs.com/del/');
end;

end.