MFC学习

最新推荐文章于 2023-04-14 11:22:58 发布

翰墨渲染流年

最新推荐文章于 2023-04-14 11:22:58 发布

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本文链接：https://blog.youkuaiyun.com/u014493318/article/details/61418880

本文介绍了如何使用MFC实现程序的单例模式，确保同一时间只能有一个实例运行，并展示了如何将已运行的实例调到前台。此外，还详细讲解了如何在MFC中发送消息给其他窗口，包括捕获鼠标、获取目标窗口句柄及发送WM_SETTEXT和WM_CLOSE消息等操作。

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让MFC程序只能运行一个：

使用互斥对象CreateMutex();

BOOL CpipeApp::InitInstance()

{

m_hMute = ::CreateMutex(NULL, FALSE, "ss");
if (GetLastError() == ERROR_ALREADY_EXISTS)
{
return FALSE;
}

}

将已运行的实例调到前台

int CpipeDlg::OnCreate(LPCREATESTRUCT lpCreateStruct)
{
if (CDialogEx::OnCreate(lpCreateStruct) == -1)
return -1;

//添加窗口属性
::SetProp(m_hWnd, AfxGetApp()->m_pszExeName, (HANDLE)1);

return 0;
}

void CpipeDlg::OnDestroy()
{
CDialogEx::OnDestroy();

::RemoveProp(m_hWnd, AfxGetApp()->m_pszExeName);
}

BOOL CpipeApp::InitInstance()

{

m_hMute = ::CreateMutex(NULL, FALSE, "ss");
if (GetLastError() == ERROR_ALREADY_EXISTS)
{

CWnd* pDesktopWnd = CWnd::GetDesktopWindow();
CWnd* pWnd = pDesktopWnd->GetWindow(GW_CHILD);
while (pWnd != NULL)
{
if (::GetProp(pWnd->m_hWnd, m_pszExeName))
{
pWnd->SetForegroundWindow();
return FALSE;
}
pWnd = pWnd->GetWindow(GW_HWNDNEXT);

}
return FALSE;
}

}

发送消息：向本窗体或外部窗体发送消息。

SendMessage();

效果图

定义几个全局变量首先：

HICON m_hIcon;
HCURSOR m_hCursor;
RECT m_rtCtrl;
BOOL m_bCapturing;
HWND m_hwndDest;

然后初始化对话框中添加：

m_hCursor = LoadCursor(NULL, IDC_SIZEALL);
GetDlgItem(IDC_CAP)->GetWindowRect(&m_rtCtrl);//picture控件Icon类型

void CSendMessageDlg::OnLButtonDown(UINT nFlags, CPoint point)
{
if (point.x >= m_rtCtrl.left && point.x <= m_rtCtrl.right
|| point.y >= m_rtCtrl.top && point.y <= m_rtCtrl.bottom)
{
m_bCapturing = true;
SetCapture();//开始捕获鼠标
SetCursor(m_hCursor);
}

CDialogEx::OnLButtonDown(nFlags, point);
}

void CSendMessageDlg::OnLButtonUp(UINT nFlags, CPoint point)
{
if (m_bCapturing)
{
ReleaseCapture();
m_bCapturing = false;
POINT pt = point;//移动到记事本里坐标
ClientToScreen(&pt);
m_hwndDest = ::WindowFromPoint(pt);

TCHAR szBuf[MAX_PATH] = { 0 };
_stprintf_s(szBuf, L"0x%.8X", m_hwndDest);
CString str;
SetDlgItemText(IDC_EDIT_HWND, szBuf);
GetClassName(m_hwndDest, szBuf, MAX_PATH);
SetDlgItemText(IDC_EDIT_CLASEENAME, szBuf);
::SendMessage(m_hwndDest, WM_GETTEXT, MAX_PATH, (LPARAM)szBuf);
SetDlgItemText(IDC_EDIT_NAME, szBuf);
}

CDialogEx::OnLButtonUp(nFlags, point);
}

void CSendMessageDlg::OnBnClickedButton1()
{
CString str;
GetDlgItemText(IDC_EDIT_NAME, str);
::SendMessage(m_hwndDest, WM_SETTEXT, 0, (LPARAM)(LPCTSTR)str);
}

void CSendMessageDlg::OnBnClickedButton2()
{
::SendMessage(m_hwndDest, WM_CLOSE, 0, 0);
}

格式化字符串：_stprintf_s

HWND hEdit = ::GetDlgItem(m_hWnd, IDC_EDIT_INPUT);//通过sendmesssage可以获取编辑框中字符串的长度
int nlen = ::SendMessage(hEdit, WM_GETTEXTLENGTH, 0, 0);
TCHAR szBuf[128] = { 0 };
_stprintf_s(szBuf, L"%d", nlen);