OpenCV在MFC窗口上画图像后，不能自动刷新,该如何处理

OpenCV在MFC窗口上画图像后，不能自动刷新
//-->>OpenCV
#include <cv.h>
#include <highgui.h>
#pragma comment(lib, "cv200.lib")
#pragma comment(lib, "cxcore200.lib")
#pragma comment(lib, "highgui200.lib")
//--<<OpenCV
PictureDlg::OnBnClickedButton1()
{
IplImage *pTempImage = cvLoadImage(_T("d:\\w.jpg"));
HDC hDC = GetDlgItem(IDC_STATIC/*Picture Control 静态图片框控件ID*/)->GetDC()->GetSafeHdc();
HWND hWnd = GetDlgItem(IDC_STATIC/*Picture Control 静态图片框控件ID*/)->m_hWnd;
RECT rect_window;
CvvImage Drawer;
::GetClientRect(hWnd, &rect_window);
Drawer.CopyOf(pTempImage);
Drawer.DrawToHDC(hDC, &rect_window);
cvReleaseImage(&pTempImage);
pTempImage = 0;
}
//图片已加载成功，但在移动窗口后，或被其它窗口档住后，被档住的静态图片框控件部份变成空白,如何解决？

------解决方案--------------------
绘制要放到OnDraw OnPaint 里啊