HOLLOW_BRUSH等价于NULL_BRUSH，都代表透明化刷

NULL_BRUSH 或HOLLOW_BRUSH和GetStockObject函数

备注：HOLLOW_BRUSH等价于NULL_BRUSH，都代表透明化刷

HGDIOBJ GetStockObject( __in  int fnObject)

    参数：fnObject代表笔或者刷的类型，可以参看MSDN

返回值：返回一个GDIOBJ对象的句柄。根据需要转换成笔/刷的句柄，

如：HBRUSH(GetStockObject(HOLLOW_BRUSH));

实例应用：一个透明的背景的编辑框

HBRUSH CBackimageDlg::OnCtlColor(CDC* pDC, CWnd* pWnd, UINT nCtlColor)

{     

       HBRUSH hbr =CDialog::OnCtlColor(pDC, pWnd, nCtlColor);

       switch(nCtlColor)             

       {            

       case CTLCOLOR_STATIC: //对所有静态文本控件的设置            

              {                   

                     pDC->SetBkMode(TRANSPARENT);//设置背景为透明                                        pDC->SetTextColor(RGB(0,0,0)); //设置字体颜色                  

                     returnHBRUSH(GetStockObject(HOLLOW_BRUSH)); // 必须                    

              }            

       case CTLCOLOR_EDIT:  //对所有编辑框控件的设置

              {                   

                     pDC->SetBkMode(TRANSPARENT);//设置背景为透明                                   pDC->SetTextColor(RGB(0,0,0)); //设置字体颜色                  

                     returnHBRUSH(GetStockObject(HOLLOW_BRUSH)); // 必须                    

              }     

       default:        

              returnCDialog::OnCtlColor(pDC,pWnd, nCtlColor);        

       }     

       return hbr;  

}

效果：

http://blog.csdn.net/qq2399431200/article/details/10991917