CLongOperation is a class designed to give visual feedback for
long-lasting operations. It has support for:
- Displaying a wait cursor
- Showing a text in the status bar
- Displaying a progress bar in a dynamically created status
bar pane
In the simplest case, this class can be used as a replacement
for MFC’s CWaitCursor:
CLongOperation wait; // some hard work going here...
To display some textual progress information in the status
bar:
CLongOperation wait; wait.SetText("Pass 1"); // ... wait.SetText("Pass 2"); // ...
To display a progress bar in the status bar:
CLongOperation wait; for (int i = 0; i < count; i++) { wait.Step((100*i)/cnt); // ... } wait.Stop();
///////////////////////////////////////////////////////////////// // LongOperation.h // (c) 1997, Klaus G|tter class CLongOperation : public CObject { public: // IDS_PLEASE_WAIT is a string resource ID for the default text, // e.g. "Please wait..." CLongOperation(UINT nIDText = IDS_PLEASE_WAIT, bool bStart = true); CLongOperation(LPCTSTR lpszText, bool bStart = true); ~CLongOperation(); void Start(); void Stop(); void Step(int nPercentage = -1); void SetText(LPCTSTR lpszText); protected: CString m_strText; bool m_bStarted; HWND m_hwndProgress; void CreateProgressControl(); }; ///////////////////////////////////////////////////////////////// // LongOperation.cpp // (c) 1997, Klaus G|tter #include "stdafx.h" #include <afxpriv.h> // defines WM_SETMESSAGESTRING #include "LongOperation.h" #ifdef _DEBUG #undef THIS_FILE #define new DEBUG_NEW static char BASED_CODE THIS_FILE[] = __FILE__; #endif CLongOperation::CLongOperation(UINT nIDText, bool bStart) : m_bStarted(false) , m_hwndProgress(NULL) { VERIFY(m_strText.LoadString(nIDText)); if (bStart) Start(); } CLongOperation::CLongOperation(LPCTSTR lpszText, bool bStart) : m_strText(lpszText) , m_bStarted(false) , m_hwndProgress(NULL) { if (bStart) Start(); } CLongOperation::~CLongOperation() { if (m_bStarted) Stop(); } void CLongOperation::Start() { if (m_bStarted) Stop(); // display text in the status bar CWnd* pMainWnd = ::AfxGetMainWnd(); if (pMainWnd) pMainWnd->SendMessage(WM_SETMESSAGESTRING, 0, (LPARAM)(LPCTSTR)m_strText); // switch on wait cursor ::AfxGetApp()->BeginWaitCursor(); m_bStarted = true; } void CLongOperation::Stop() { if (!m_bStarted) return; if (m_hwndProgress) { // clean up and destroy progress bar CStatusBar* pStatusBar = DYNAMIC_DOWNCAST(CStatusBar, CWnd::FromHandle(::GetParent(m_hwndProgress))); ASSERT_VALID(pStatusBar); ::DestroyWindow(m_hwndProgress); m_hwndProgress = NULL; // remove progress bar pane int anPart[32]; int nParts = pStatusBar->GetStatusBarCtrl().GetParts(31, anPart); nParts--; pStatusBar->GetStatusBarCtrl().SetParts(nParts, anPart+1); } // switch back to standard text in the status bar CWnd* pMainWnd = ::AfxGetMainWnd(); if (pMainWnd) pMainWnd->SendMessage(WM_SETMESSAGESTRING, AFX_IDS_IDLEMESSAGE, 0); // switch off wait cursor ::AfxGetApp()->EndWaitCursor(); m_bStarted = false; } void CLongOperation::Step(int nPercentage) { if (!m_bStarted) Start(); ::AfxGetApp()->RestoreWaitCursor(); if (nPercentage >= 0) { ASSERT(nPercentage <= 100); // create or update a progress control in the status bar if (m_hwndProgress == NULL) CreateProgressControl(); if (m_hwndProgress) ::SendMessage(m_hwndProgress, PBM_SETPOS, (WPARAM)nPercentage, 0); } } void CLongOperation::SetText(LPCTSTR lpszText) { m_strText = lpszText; CWnd* pMainWnd = ::AfxGetMainWnd(); if (pMainWnd) pMainWnd->SendMessage(WM_SETMESSAGESTRING, 0, (LPARAM)(LPCTSTR)m_strText); } void CLongOperation::CreateProgressControl() { ASSERT(m_hwndProgress == NULL); // find status bar CWnd* pMainWnd = ::AfxGetMainWnd(); if (pMainWnd == NULL) return; CStatusBar* pStatusBar = DYNAMIC_DOWNCAST(CStatusBar, pMainWnd->GetDescendantWindow(AFX_IDW_STATUS_BAR, TRUE)); if (pStatusBar == NULL || pStatusBar->m_hWnd == NULL) return; CRect rc; // this will be the location for the progress bar pane pStatusBar->GetItemRect(0, rc); if (!m_strText.IsEmpty()) { // adjust so that the text in the leftmost pane will not be covered CClientDC dc(pStatusBar); dc.SelectObject(pStatusBar->GetFont()); CSize sz = dc.GetTextExtent(m_strText); TEXTMETRIC tm; dc.GetTextMetrics(&tm); rc.left += sz.cx + 2*tm.tmAveCharWidth; } int cx = rc.Width(); if (cx < 20) { // no sense in displaying such a small progress bar TRACE0("ProgressDisplay would be too smalln"); return; } else if (cx > 200) { // arbitrarily limiting progress bar width to 200 pixel cx = 200; rc.left = rc.right - cx; } // add a pane between the text and the currently leftmost pane int anPart[32]; int nParts = pStatusBar->GetStatusBarCtrl().GetParts(31, anPart+1); anPart[0] = rc.left; nParts++; pStatusBar->GetStatusBarCtrl().SetParts(nParts, anPart); pStatusBar->GetStatusBarCtrl().GetRect(1, rc); // create progress bar control m_hwndProgress = ::CreateWindow(PROGRESS_CLASS, "", WS_CHILD | WS_VISIBLE, rc.left, rc.top, rc.Width(), rc.Height(), pStatusBar->m_hWnd, (HMENU)1, AfxGetInstanceHandle(), NULL); pStatusBar->UpdateWindow(); }