C / C++ / MFC

long CMHandle = (long)(((CMainFrame*)AfxGetMainWnd())->m_wndStatusBar.m_WzdProgressCtrl).GetSafeHwnd();

code>pView->SendMessage(WM_COMMAND,IDC_BUTTONHIDDEN1,0);</code>

BM_CLICK
An application sends a BM_CLICK message to simulate the user clicking a button. This message causes the button to receive the WM_LBUTTONDOWN and WM_LBUTTONUP messages, and the button's parent window to receive a BN_CLICKED notification message.

To send this message, call the SendMessage function with the following parameters. 

SendMessage(
  (HWND) hWnd,         // handle to destination window 
  BM_CLICK,            // message to send
  (WPARAM) wParam,     // not used; must be zero
  (LPARAM) lParam      // not used; must be zero
);

CWnd* pWnd = ...;  // get target window/dialog/view
pWnd->SendMessage (WM_COMMAND, IDC_BUTTONHIDDEN1);

Call SendMessage(hBtnHandle, BM_CLICK, byval 0&, byval 0&)

Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Any) As Long

Call SendMessage(hViewHandle, WM_COMMAND, IDC_HIDDEN_BUTTON_1, 0);

void doSomething();  // do something

void CMyView::doSomething()
{
  SendMessage (WM_COMMAND, IDC_BUTTONHIDDEN1);
}