这样的代码为何会导致死机??

[zhuliangsu]

这样的代码为何会导致死机??

void CMainFrame::OnPaint()
{

CRect rc;
CDC dc;

dc.m_hDC=::GetDC(this->m_hWndMDIClient);

CBrush br(RGB(120,200,120));

dc.SelectObject(&br);

GetClientRect(&rc);

dc.PatBlt(rc.left,rc.top,rc.Width(),rc.Height(),PATCOPY);

ReleaseDC(&dc);

}

[hugwind]

可能这一句有问题：dc.m_hDC=::GetDC(this->m_hWndMDIClient);
最好能在前面加一句if(this->m_hWndMDIClient==NULL) return;

[bcpl]

不知道为什么为死机，也不敢试：（
象下面这样写应该没问题

void CMainFrame::OnPaint()
{

CRect rc;
CDC dc;

dc.Attach(::GetDC(this->m_hWndMDIClient));

CBrush br(RGB(120,200,120));

CBrush *pOldBrush = (CBrush*)dc.SelectObject(&br);

GetClientRect(&rc);

dc.PatBlt(rc.left,rc.top,rc.Width(),rc.Height(),PATCOPY);

dc.SelectObject(pOldBrush);

ReleaseDC(&dc);
dc.Detach();

}