用如下代码动态调整RichEdit控件的大小，请问哪里错了？？
void CNoteBookDlg::OnSize(UINT nType, int cx, int cy)
{
    CDialog::OnSize(nType, cx, cy);
    
    // TODO: Add your message handler code here
    SetEditRect();
}

void CNoteBookDlg::SetEditRect()
{
    CRect rectClient;
    GetWindowRect(rectClient);
    ScreenToClient(rectClient);

    int nTop    = rectClient.top;
    int nLeft   = rectClient.left;
    int nWidth  = rectClient.Width();
    int nHeight = rectClient.Height();

    GetDlgItem(IDC_RICHEDIT_MAIN)->MoveWindow(nTop, nLeft, nWidth, nHeight);
}
//IDC_RICHEDIT_MAIN是RichEdit的ID。RichEdit已使用AfxInitRichEdit()初始化。
//编译能通过，但运行时会出错。

请高手帮忙，谢谢了！