C#滑鼠滾輪處理滾動條滾動

 //滑鼠進入控件的可見部分

        private void PictureBox_MouseEnter(object sender, EventArgs e)

        {

            this.Focus();

        }

 //處理滑鼠滾輪//當e.Delta > 0時滑鼠滾輪是向上滾動，e.Delta < 0時滑鼠滾輪向下滾動。

        protected override void OnMouseWheel(System.Windows.Forms.MouseEventArgs e)

        {

            if (e.Delta > 0)

            {

               if ((vScrollBar1.Value - 10) < vScrollBar1.Minimum)

                {

                    vScrollBar1.Value = vScrollBar1.Minimum;

                }

                else

                 {

                    vScrollBar1.Value -=10;

                }

            }

            else

            {

                if ((vScrollBar1.Value+10) > vScrollBar1.Maximum)

                {

                    vScrollBar1.Value = vScrollBar1.Maximum;

                }

               else

                {

                    vScrollBar1.Value += 10;

                }

            }

     }