Добавить событие onDblClick на заголовке TListView

Code:

{

MS did not see fit to send a notification to the listview when the user

Double - clicks on the header. But the header control class does have the

CS_DBLCLKS Style, so it does get WM_LBUTTONDBLCLK messages, it just does

not do anything with them. To get at these messages requires API - Style

subclassing of the header control.

}

uses commctrl;

function HeaderProc(wnd: HWND; Msg: Cardinal; wParam: wParam; lParam: lParam): Longint;

  stdcall;

var

  hti: THDHitTestInfo;

begin

  Result := CallWindowProc(Pointer(GetWindowLong(wnd, GWL_USERDATA)),

    wnd, Msg, wParam, lParam);

  if Msg = WM_LBUTTONDBLCLK then

  begin

    FillChar(hti, SizeOf(hti), 0);

    hti.Point := SmallPointToPoint(TSmallPoint(lParam));

    if SendMessage(wnd, HDM_HITTEST, 0, Longint(@hti)) >= 0 then

      if hti.Flags = HHT_ONHEADER then

        // would usually send a custom notification to GetParent(wnd) here

       Form1.Memo1.Lines.Add(Format('doubleclick on header item %d', [hti.Item]));

  end;

end;

procedure TForm1.Button1Click(Sender: TObject);

var

  wnd: HWND;

  buffer: array [0..80] of Char;

  oldProc: Integer;

begin

  wnd := GetWindow(Listview1.Handle, GW_CHILD);

  if wnd <> 0 then

  begin

    Windows.GetClassname(wnd, buffer, SizeOf(buffer));

    memo1.Text := buffer;

    if (GetClassLong(wnd, GCL_STYLE) and CS_DBLCLKS) <> 0 then

    begin

      Memo1.Lines.Add('Has doubleclicks style');

      oldproc := GetWIndowLong(wnd, GWL_WNDPROC);

      if GetWindowLong(wnd, GWL_USERDATA) <> 0 then

        raise Exception.Create('Cannot sublcass header, USERDATA already in use');

      SetWIndowLong(wnd, GWL_USERDATA, oldproc);

      SetWindowLong(wnd, GWL_WNDPROC, Integer(@HeaderProc));

    end;

  end

  else

    Memo1.Text := 'No child';

end;