FlowLayoutPanel 支持中键滚轮滚动

原贴:http://blog.sina.com.cn/s/blog_6b965dd70101po76.html

FlowLayoutPanel控件不直接支持MouseWheel事件.即滚动滚轮也不会响应.所以必须手动来支持响应滚轮.

查看了一下FlowLayoutPanel控件的源码,原来FlowLayoutPanel控件是继承于Panel控件的.

所以,Panel控件也是直接不支持MouseWheel事件来进行滚动滚轮的.

你可以添加MouseWheel事件,然后写上支持滚动的功能.也可以直接重写该控件.这样可以复用该控件.

如果只支持MouseWheel事件,还是不一定在滚动滚轮的时候,就能引发MouseWheel事件.所以,必须让鼠标停留在控件上时,让控件处于输入焦点状态.这是,滚动滚轮就可以引发MouseWheel事件了.

废话不多说,贴出代码

     ///

    /// 支持滚轮的FlowLayoutPanel.

    ///

    class ScrollFlowLayoutPanel : FlowLayoutPanel

    {

        public ScrollFlowLayoutPanel()

        {

          

        }

        protected override void OnMouseClick(MouseEventArgs e)

        {

            this.Focus();

            base.OnMouseClick(e);

        }

        protected override void OnMouseEnter(EventArgs e)

        {

            this.Focus();

            base.OnMouseEnter(e);

        }

        protected override void OnMouseWheel(MouseEventArgs e)

        {

            if (e.Delta < 0)

            {

                if (this.VerticalScroll.Maximum > this.VerticalScroll.Value + 50)

                    this.VerticalScroll.Value += 50;

                else

                    this.VerticalScroll.Value = this.VerticalScroll.Maximum;

            }

            else

            {

                if (this.VerticalScroll.Value > 50)

                    this.VerticalScroll.Value -= 50;

                else

                {

                    this.VerticalScroll.Value = 0;

                }

            }

            

        }

    }

将继承的FlowLayoutPanel修改为Panel,就可以支持Panel的滚轮滚动了.