Добавить событие onDblClick на заголовке TListView

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Добавить событие onDblClick на заголовке TListView[править | править код]

{ 
  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;


Source: Взято с сайта: http://www.swissdelphicenter.ch
ID: 01131