XtraTabControl（DEV中选项卡）分页实现拖拽 效果

用到的命名空间是：

    using DevExpress.XtraTab;

    using DevExpress.XtraTab.ViewInfo;

用到的变量:

    private Rectangle rectDragBoxFromMouseDown;

    private bool isDragging = false;

    private Point dragOffset = Point.Empty;

创建所用到的函数:

    private void CalcRectDragBox(int x, int y)

    {

        // Remember the point where the mouse down occurred. The DragSize indicates

        // the size that the mouse can move before a drag event should be started.

        Size dragSize = SystemInformation.DragSize;

        // Create a rectangle using the DragSize, with the mouse position being

        // at the center of the rectangle.

        rectDragBoxFromMouseDown = new Rectangle(new Point((int)x - (dragSize.Width / 2), (int)y - (dragSize.Height / 2)), dragSize);

    }

    private int FindIndex(XtraTabPage page)

    {

        int i = 0;

        while (i < xtcMain.TabPages.Count)

        {

            if (xtcMain.TabPages[i].Equals(page))

            {

                return i;

            }

            i += 1;

        }

        return -1;

    }

在 DragOver 事件中的code：

    XtraTabHitInfo hinfo = default(XtraTabHitInfo);

    XtraTabPage hoverTab = default(XtraTabPage);

    XtraTabPage dragTab = default(XtraTabPage);

    XtraTabPage selTab = default(XtraTabPage);

    XtraTabPage repTab = default(XtraTabPage);

    //

    int itemDragIndex = 0;

    int dropLocationIndex = 0;

    //

    // get the tab we are hovering over.

    hinfo = xtcMain.CalcHitInfo(xtcMain.PointToClient(new Point(e.X, e.Y)));

    //

    if ((hinfo.Page != null))

    {

        hoverTab = hinfo.Page;

        //Make sure there is a TabPage being dragged.

        if (e.Data.GetDataPresent(typeof(XtraTabPage)))

        {

            e.Effect = DragDropEffects.Move;

            dragTab = (XtraTabPage)e.Data.GetData(typeof(XtraTabPage));

            // can't use the TabIndex on the control because it changes

            // when we move the tab page.

            itemDragIndex = FindIndex(dragTab);

            dropLocationIndex = FindIndex(hoverTab);

            //Don't do anything if we are hovering over ourself.

            if (itemDragIndex != dropLocationIndex)

            {

                selTab = xtcMain.TabPages[itemDragIndex];

                repTab = xtcMain.TabPages[dropLocationIndex];

                //

                xtcMain.TabPages.Move(dropLocationIndex, selTab);

                xtcMain.TabPages.Move(itemDragIndex, repTab);

                xtcMain.SelectedTabPage = selTab;

            }

        }

    }

    else

    {

        e.Effect = DragDropEffects.None;

    }

在 MouseDown 事件中的code：

    CalcRectDragBox(e.X, e.Y);





    // Handle Mouse move only if left button is pressed.

    if (e.Button == MouseButtons.Left)

    {

        // If the mouse moves outside the rectangle, start the drag.

        if (!rectDragBoxFromMouseDown.Equals(Rectangle.Empty) & !rectDragBoxFromMouseDown.Contains(e.X, e.Y))

        {

            isDragging = true;

            dragOffset = new Point(e.X, e.Y);

            Invalidate();

            // Proceed with the drag and drop.

            DragDropEffects dropEffect = DoDragDrop(xtcMain.SelectedTabPage, DragDropEffects.Move);

            // Reset the drag box to avoid reentry of drag.

            CalcRectDragBox(e.X, e.Y);

            isDragging = false;

            dragOffset = Point.Empty;

            Invalidate();

        }

    }

如果你有不同大小的标签，张贴的代码将导致快如闪电的标签之间切换，如果您对重叠的区域的大小不同悬停。 为了防止这种情况，我只是说在dragOver处理一个简单的标志，忽略未来DragOver事件。 在上面的DragOver里面相应的 位置加入这个标志ignoreNextDrag，具体代码如下：

    if (itemDragIndex != dropLocationIndex && !ignoreNextDrag)

    {

        ignoreNextDrag = true;

        selTab = tabControlClientModules.TabPages[itemDragIndex];

        repTab = tabControlClientModules.TabPages[dropLocationIndex];

        //

        tabControlClientModules.TabPages.Move(dropLocationIndex, selTab);

        tabControlClientModules.TabPages.Move(itemDragIndex, repTab);

        tabControlClientModules.SelectedTabPage = selTab;

    }

    else

    {

        ignoreNextDrag = false;



    }