How do I show progress in status/task bar button using Delphi 7?

Question

If you copy files under Windows 7, you will see the progress of the copy in a sort of progress bar begin displayed in the status or task bar button of the application.

Can this be achieved using Delphi 7 ?

I have some lengthy operation which would be ideally suited to show it's progress this way.

sample of such a button using copy with Total Commander

.

Answer 1

Use the ITaskbarList3 interface for that, specifically its SetProgressState and SetProgressValue methods. Use CoCreateInstance() specifying CLSID_TaskbarList and IID_ITaskbarList3 to access the interface.

For example:

type
  ITaskbarList = interface(IUnknown) 
    ['{56FDF342-FD6D-11D0-958A-006097C9A090}']
    function HrInit: HRESULT; stdcall;
    function AddTab(hwnd: HWND): HRESULT; stdcall;
    function DeleteTab(hwnd: HWND): HRESULT; stdcall;
    function ActivateTab(hwnd: HWND): HRESULT; stdcall;
    function SetActiveAlt(hwnd: HWND): HRESULT; stdcall;
  end;

  ITaskbarList2 = interface(ITaskbarList) 
    ['{602D4995-B13A-429B-A66E-1935E44F4317}']
    function MarkFullscreenWindow(hwnd: HWND; 
      fFullscreen: BOOL): HRESULT; stdcall;
  end;

  THUMBBUTTON = record 
    dwMask: DWORD;
    iId: UINT;
    iBitmap: UINT;
    hIcon: HICON;
    szTip: packed array[0..259] of WCHAR;
    dwFlags: DWORD;
  end;
  TThumbButton = THUMBBUTTON;
  PThumbButton = ^TThumbButton;

  ITaskbarList3 = interface(ITaskbarList2) 
    ['{EA1AFB91-9E28-4B86-90E9-9E9F8A5EEFAF}']
    function SetProgressValue(hwnd: HWND; ullCompleted: ULONGLONG; 
      ullTotal: ULONGLONG): HRESULT; stdcall;
    function SetProgressState(hwnd: HWND; 
      tbpFlags: Integer): HRESULT; stdcall;
    function RegisterTab(hwndTab: HWND; hwndMDI: HWND): HRESULT; stdcall;
    function UnregisterTab(hwndTab: HWND): HRESULT; stdcall;
    function SetTabOrder(hwndTab: HWND; 
      hwndInsertBefore: HWND): HRESULT; stdcall;
    function SetTabActive(hwndTab: HWND; hwndMDI: HWND; 
      tbatFlags: Integer): HRESULT; stdcall;
    function ThumbBarAddButtons(hwnd: HWND; cButtons: UINT;
      pButton: PThumbButton): HRESULT; stdcall;
    function ThumbBarUpdateButtons(hwnd: HWND; cButtons: UINT;
      pButton: PThumbButton): HRESULT; stdcall;
    function ThumbBarSetImageList(hwnd: HWND; 
      himl: HIMAGELIST): HRESULT; stdcall;
    function SetOverlayIcon(hwnd: HWND; hIcon: HICON; 
      pszDescription: LPCWSTR): HRESULT; stdcall;
    function SetThumbnailTooltip(hwnd: HWND; 
      pszTip: LPCWSTR): HRESULT; stdcall;
    function SetThumbnailClip(hwnd: HWND; 
      var prcClip: TRect): HRESULT; stdcall;
  end;

const
  CLSID_TaskbarList: TGUID = '{56FDF344-FD6D-11d0-958A-006097C9A090}';
  TBPF_NOPROGRESS    = 0; 
  TBPF_INDETERMINATE = $1; 
  TBPF_NORMAL        = $2; 
  TBPF_ERROR         = $4; 
  TBPF_PAUSED        = $8; 

var
  TBL: ITaskbarList3;
  I: Integer;
begin
  CoCreateInstance(CLSID_TaskbarList, nil, CLSCTX_INPROC, ITaskbarList3, TBL);

  if (TBL <> nil) then 
    TBL.SetProgressState(Application.Handle, TBPF_INDETERMINATE);
  try
    for I := 0 to 100 do
    begin
      if (TBL <> nil) then 
        TBL.SetProgressValue(Application.Handle, I, 100);
      Sleep(1000);
    end;
  finally
    if (TBL <> nil) then 
      TBL.SetProgressState(Application.Handle, TBPF_NOPROGRESS);
  end;
end;