IDC_STATIC是静态文本框的ID

void CTextDlg::OnBnClickedButton1()
{
	SetDlgItemText(IDC_STATIC, TEXT("hello"));
}


void CTextDlg::OnBnClickedButton2()
{
	CString str;
	GetDlgItem(IDC_STATIC)->GetWindowText(str);
	MessageBox(str);
}