How to attach context menu to TChromium browser

问题

I have a TChromium broser from Delphi Chromium Embedded (http://code.google.com/p/delphichromiumembedded). I would like to attach a context menu to it. How I can achieve that?

回答1:

You need to handle the OnBeforeMenu event. In that event handler is enough to set the output parameter Result to True what will suppress the default context menus to popup. After that you can display your own menu on the positions obtained from the menuInfo structure.

Here's the code sample with a custom popup menu:

uses
  ceflib, cefvcl;

procedure TForm1.FormCreate(Sender: TObject);
begin
  Chromium1.Load('www.example.com');
end;

procedure TForm1.Chromium1BeforeMenu(Sender: TObject;
  const browser: ICefBrowser; const menuInfo: PCefHandlerMenuInfo;
  out Result: Boolean);
begin
  Result := True;
  PopupMenu1.Popup(menuInfo.x, menuInfo.y);
end;

procedure TForm1.PopupMenuItemClick(Sender: TObject);
begin
  ShowMessage('You''ve clicked on a custom popup item :)');
end;

Update:

For dynamically created instance you have to assign the event handler manually. Try the following code.

uses
  ceflib, cefvcl;

type
  TForm1 = class(TForm)
    Panel1: TPanel;
    Button1: TButton;
    PopupMenu1: TPopupMenu;
    procedure Button1Click(Sender: TObject);
  private
    procedure ChromiumOnBeforeMenu(Sender: TObject;
      const browser: ICefBrowser; const menuInfo: PCefHandlerMenuInfo;
      out Result: Boolean);
  public
    { Public declarations }
  end;

implementation

procedure Form1.ChromiumOnBeforeMenu(Sender: TObject; const browser: ICefBrowser;
  const menuInfo: PCefHandlerMenuInfo; out Result: Boolean);
begin
  Result := True;
  PopupMenu1.Popup(menuInfo.x, menuInfo.y);
end;

procedure TForm1.Button1Click(Sender: TObject);
var
  Chromium: TChromium;
begin
  // owner is responsible for destroying the component
  // in this case you are telling to Panel1 to destroy
  // the Chromium instance before he destroys itself,
  // it doesn't affect the event handling
  Chromium := TChromium.Create(Panel1);

  Chromium.Parent := Panel1;
  Chromium.Left := 10;
  Chromium.Top := 10;
  Chromium.Width := Panel1.Width - 20;
  Chromium.Height := Panel1.Height - 20;

  // this line is important, you are assigning the event
  // handler for OnBeforeMenu event, so in fact you tell
  // to the Chromium; hey if the OnBeforeMenu fires, run
  // the code I'm pointing at, in this case will execute
  // the ChromiumOnBeforeMenu procedure
  Chromium.OnBeforeMenu := ChromiumOnBeforeMenu;

  Chromium.Load('www.example.com');
end;

回答2:

actually you dont need popupmenu and you dont have to have add vcl.menus unit into your application if you have already can build chromium's context menu. also chromium's own menu is more modern and clear look like and faster draw perfrmance rather than a vcl which uses vintage win32 api library.

cef3 has its menu totally configurable like this.

 procedure Tfmmain.Chromium1BeforeContextMenu(Sender: TObject;
    const browser: ICefBrowser; const frame: ICefFrame;
    const params: ICefContextMenuParams; const model: ICefMenuModel);
  begin
    model.Clear;
    model.AddItem(1, 'Your Command 1');
    model.AddItem(2, 'Your Command 2');
    model.AddSeparator;
    model.AddItem(3, 'Your Command 3');
    model.AddItem(4, 'your Command 4');
    model.AddSeparator;
    model.AddItem(999, 'Quit');

    model.SetAccelerator(1, VK_RIGHT, false, false, false);
    model.SetAccelerator(2, VK_LEFT, false, false, false);

    model.SetAccelerator(3, VK_DOWN, false, false, false);
    model.SetAccelerator(4, VK_UP, false, false, false);

    model.SetAccelerator(999, VK_ESCAPE, false, false, false);

  end;

---

  procedure Tfmmain.Chromium1ContextMenuCommand(Sender: TObject;
    const browser: ICefBrowser; const frame: ICefFrame;
    const params: ICefContextMenuParams; commandId: Integer;
    eventFlags: TCefEventFlags; out Result: Boolean);
  begin
    case commandId of
      1:
        begin
           DoIt1;
          Result := true;
        end;
      2:
        begin
         DoIt2;
          Result := true;
        end;
      3:
        begin
        DoIt3;
          Result := true;
        end;
      4:
       DoIt4;
          Result := true;
        end;
      999:
        begin
          Application.MainForm.Close;
           Result := true;
        end;
    end;

  end;

---

note:SetAccelerator shortcuts only functional if popup appears.so you may need onPreKeyEvent

来源：https://stackoverflow.com/questions/8408077/how-to-attach-context-menu-to-tchromium-browser