滚动条效果

Question

 if (QueryResultDGV.DataSource != null)//QueryResultDGV是datagridview控件
            {
                if (QueryResultDGV.FirstDisplayedScrollingColumnIndex < hScrollBar1.Value)
                {
                    QueryResultDGV.FirstDisplayedScrollingColumnIndex += hScrollBar1.LargeChange;
                }
                else if (QueryResultDGV.FirstDisplayedScrollingColumnIndex > hScrollBar1.Value)
                {
                    QueryResultDGV.FirstDisplayedScrollingColumnIndex -= hScrollBar1.LargeChange;
                }
            }

Answer 1

 QueryResultDGV.FirstDisplayedScrollingColumnIndex += hScrollBar1.LargeChange;
这样注册两次的话,事件触发会执行两次代码的
滚动条好好的为啥要这样做??