/// <summary>
        /// Method to handle when a child has been selected from a node
        /// </summary>
        /// <param name="sender">Sender of this Event</param>
        /// <param name="e">Event Arguments</param>
        private void NodeButtonClicked(Object sender, EventArgs e)
        {
            if (sender.GetType() == typeof(SEAddressBarDropDownItem) || sender.GetType() == typeof(SEAddressBarButton))
            {
                IAddressNode addressNode;

                if (sender.GetType() == typeof(SEAddressBarDropDownItem))
                {
                    SEAddressBarDropDownItem tsb = (SEAddressBarDropDownItem)sender;
                    addressNode = tsb.AddressNode;
                }
                else
                {
                    SEAddressBarButton tsb = (SEAddressBarButton)sender;
                    addressNode = tsb.AddressNode;
                }

                //set the current node
                _currentNode = addressNode;

                //cxs
                //用不着整个都重新加载,在当前最后一个Item后面加上点的这个就行了
                //但是要额外考虑点击的是哪个下拉按钮,如果是中间的,还是要整个刷
                ResetBar();
                //if (sender.GetType().Equals(typeof(SEAddressBarButton)))
                //{
                //    UpdateBar();
                //}
                //else
                //{
                //    AddToolStripItemUpdate(ref _currentNode,ButtonPosition.Behind);
                //}

                //if the selection changed event is handled
                if (SelectionChange != null)
                {
                    NodeChangedArgs args = new NodeChangedArgs(_currentNode.UniqueID);
                    SelectionChange(this, args);
                }

                return;
            }
        }
        /// <summary>
        /// 根据IAddressNode地址栏对象,创建并添加一个地址栏按钮
        /// </summary>
        /// <param name="node">The node to base the item on</param>
        /// <returns>Built SEAddressBarDropDownItem. Returns Null if method failed</returns>
        private void AddToolStripItemUpdate(IAddressNode node, ButtonPosition position)
        {
            SEAddressBarButton tsButton = null;

            node.CreateChildNodes();

            tsButton = new SEAddressBarButton(node.DisplayName, node.Icon, NodeButtonClicked);

            tsButton.AddressNode        = node;
            tsButton.ImageAlign         = ContentAlignment.MiddleCenter;
            tsButton.DoubleClickEnabled = true;
            tsButton.DoubleClick       += new EventHandler(NodeDoubleClickHandler);

            AddAddressBarButton(tsButton, position);

            if (IsManyNodes())
            {
                CreateOverflowDropDown();
            }
        }
        /// <summary>
        /// 添加一个地址栏项
        /// </summary>
        /// <param name="button"></param>
        /// <param name="position"></param>
        private void AddAddressBarButton(SEAddressBarButton button, ButtonPosition position)
        {
            //如果当前显示了最左下拉菜单,就需要直接加在最左下拉菜单下
            //如果直接加左边,可能整个地址条是够显示的,就造成这一项出现在最左下拉前面
            //并且如果直接加在最左下拉下面,就不用去管是否还有子级了,因为不需要显示那个向下箭头了
            if (this.Items.Contains(_overflowButton))
            {
                SEAddressBarDropDownItem dropDownItem = new SEAddressBarDropDownItem(button.Text, button.Image, NodeButtonClicked);
                dropDownItem.AddressNode = button.AddressNode;
                //_overflowButton.DropDown.Items.Add(dropDownItem);
                _overflowDropDown.Items.Add(dropDownItem);
            }
            else
            {
                //处理子级,如果需要,需要显示一个向下箭头
                BuildChildItem(button);

                if (position == ButtonPosition.Behind)
                {
                    this.Items.Add(button);
                    if (button.DropDownButton != null)
                    {
                        this.Items.Add(button.DropDownButton);
                    }

                    _buttonList.Add(button);
                }
                else
                {
                    this.Items.Insert(0, button);
                    if (button.DropDownButton != null)
                    {
                        this.Items.Insert(1, button.DropDownButton);
                    }

                    _buttonList.Insert(0, button);
                }
            }
        }
        /// <summary>
        /// 创建指定地址栏项的子级(如果需要)
        /// </summary>
        /// <param name="button"></param>
        private void BuildChildItem(SEAddressBarButton button)
        {
            IAddressNode addressNode = button.AddressNode;

            SEAddressBarDropDownButton dropDownButton = null;

            //SEAddressBarDropDown dropDown = null;

            if (addressNode.Children != null && addressNode.Children.Length > 0)
            {
                dropDownButton        = new SEAddressBarDropDownButton(String.Empty);
                button.DropDownButton = dropDownButton;

                //check if we have any tag data (we cache already built drop down items in the node TAG data.
                if (addressNode.DropDownMenu == null)
                {
                    addressNode.DropDownMenu = GetButtonDropDown(addressNode);
                }
                else
                {
                    if (addressNode.DropDownMenu.GetType() == typeof(SEAddressBarDropDown))
                    {
                        //dropDown = (SEAddressBarDropDown)addressNode.DropDownMenu;

                        foreach (SEAddressBarDropDownItem tsmi in addressNode.DropDownMenu.Items)
                        {
                            if (tsmi.Font.Style != _baseFont.Style)
                            {
                                tsmi.Font = _baseFont;
                            }
                        }
                    }
                }

                dropDownButton.DropDown     = addressNode.DropDownMenu;
                dropDownButton.DisplayStyle = ToolStripItemDisplayStyle.None;
                dropDownButton.ImageAlign   = ContentAlignment.MiddleCenter;
            }
        }
        /// <summary>
        /// 创建最左下拉菜单
        /// </summary>
        private void CreateOverflowDropDown()
        {
            //在最左边添加下拉菜单
            if (this.Items.Contains(_overflowButton) == false)
            {
                this.Items.Insert(0, _overflowButton);
                _overflowButton.OwnerChanged += new EventHandler(OverflowDestroyed);

                if (this.DropDownRenderer != null)
                {
                    _overflowDropDown.Renderer = this.DropDownRenderer;
                }
            }

            /*
             * 把第一项移到前下拉里,然后测试是否还是不够显示,如果还是不够
             * 再次把第一项移到前下拉里,如此反复
             * 但有一点,需判断第一项是否就是当前项,如果就是当前项,则表示是当前项显示文本太长
             * 所以不够显示,需要截断当前项的显示文本
             */

            _overflowDropDown.Items.Clear();

            while (true)
            {
                SEAddressBarButton frontButton = _buttonList[0];

                //如果当前节点已经是最右边的节点了
                if (_currentNode == frontButton.AddressNode)
                {
                    //计算可以显示的宽度
                    int itemWidth = 0;
                    foreach (ToolStripItem item in frontButton.Owner.Items)
                    {
                        if (item == frontButton)
                        {
                            continue;
                        }

                        itemWidth += item.Width;
                    }
                    itemWidth = frontButton.Owner.Width - itemWidth - 40;

                    frontButton.Text = AdjustTextForDisplay(frontButton.Text, itemWidth, frontButton.Font);
                    break;


                    ////通过截断显示字符串的方式以让它能显示得下
                    ////简单起见,直接截一半,暂时不去测量文本了,截完以后需继续判断,不行再截一半,直到截到最后个字符
                    //if (frontButton.Text.Length <= 1)
                    //{
                    //    break;
                    //}
                    //else
                    //{
                    //    frontButton.Text = frontButton.Text.Substring(0, frontButton.Text.Length / 2) + "...";
                    //    if (IsManyNodes())
                    //    {
                    //        CreateOverflowDropDown();
                    //    }
                    //    break;
                    //}
                }
                else
                {
                    SEAddressBarDropDownItem dropDownItem = null;
                    dropDownItem             = new SEAddressBarDropDownItem(frontButton.Text, frontButton.Image, NodeButtonClicked);
                    dropDownItem.AddressNode = frontButton.AddressNode;

                    //把靠左边的第一个项移入最左下拉菜单的顶部
                    _overflowDropDown.Items.Insert(0, dropDownItem);

                    this.Items.Remove(frontButton);
                    if (frontButton.DropDownButton != null)
                    {
                        this.Items.Remove(frontButton.DropDownButton);
                    }

                    _buttonList.Remove(frontButton);
                }

                if (IsManyNodes() == false)
                {
                    break;
                }
            }
        }