MFC的SendMessage用法

Cwnd::SendMessage函数将直接调用窗口过程，并且在该窗口处理该消息之前，不会返回。 这与PostMessage成员函数不同，后者将消息放入窗口的消息队列，并立即返回。

函数声明：

LRESULT SendMessage(UINT message, WPARAM wParam = 0,LPARAM lParam = 0);

具体的用法：

void CAboutDlg::OnPaint()
{
   // This code, normally emitted by the Application Wizard for a dialog-
   // based project for the dialog's WM_PAINT handler, runs only if the
   // window is iconic. The window erases the icon's area, then
   // paints the icon referenced by m_hIcon.
   if (IsIconic())
   {
      CPaintDC dc(this); // device context for painting

      SendMessage(WM_ICONERASEBKGND, (WPARAM)dc.GetSafeHdc(), 0);

      // Center icon in client rectangle
      int cxIcon = GetSystemMetrics(SM_CXICON);
      int cyIcon = GetSystemMetrics(SM_CYICON);
      CRect rect;
      GetClientRect(&rect);
      int x = (rect.Width() - cxIcon + 1) / 2;
      int y = (rect.Height() - cyIcon + 1) / 2;

      // Draw the icon
      dc.DrawIcon(x, y, m_hIcon);
   }
   else
   {
      CDialog::OnPaint();
   }
}

 

来源：CSDN

作者：淡月明

链接：https://blog.csdn.net/sinat_31608641/article/details/103780020