TabWindow.TabWindow tabWin = new TabWindow.TabWindow();
TextBox tb = new TextBox();
tb.Text = "Test Demo";
tabWin.AddTabItem(tb.Text, tb);
tabWin.Show();

<ControlTemplate TargetType="{x:Type Button}"><Border x:Name="buttonBorder" CornerRadius="2" Background="{TemplateBinding Background}" BorderBrush="DarkGray" BorderThickness="1"><Path x:Name="buttonPath" Margin="2" Stroke="DarkGray" StrokeThickness="2" StrokeStartLineCap="Round" StrokeEndLineCap="Round" Stretch="Fill" ><Path.Data><PathGeometry><PathFigure StartPoint="0,0"><LineSegment Point="13,13"/></PathFigure><PathFigure StartPoint="0,13"><LineSegment Point="13,0"/></PathFigure></PathGeometry></Path.Data></Path></Border><ControlTemplate.Triggers>...</ControlTemplate.Triggers>
</ControlTemplate>

如下所示，此关闭按钮样式将应用于选项卡标题模板。DockPanel由停靠在最右侧的[X]和标头ContentPresenter组成。[x]按钮的默认可见性被隐藏。选择选项卡后，它变为可见。用于Trigger显示或隐藏[x]按钮。

<Style TargetType="{x:Type local:CloseEnabledTabItem}">
...<Setter Property="Template"><Setter.Value><ControlTemplate TargetType="{x:Type local:CloseEnabledTabItem}"><Grid SnapsToDevicePixels="true" IsHitTestVisible="True" x:Name="gridHeader"><Border x:Name="tabItemBorder" Background="{TemplateBinding Background}" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="1,1,1,0" ><DockPanel x:Name="tabItemDockPanel"><Button x:Name="tabItemCloseButton" Style="{StaticResource tabItemCloseButtonStyle}" DockPanel.Dock="Right" Margin="3,0,3,0" Visibility="Hidden" /><ContentPresenter x:Name="tabItemContent" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" RecognizesAccessKey="True" VerticalAlignment="{TemplateBinding VerticalContentAlignment}" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" ContentSource="Header" Margin="{TemplateBinding Padding}"/></DockPanel></Border></Grid>...</ControlTemplate></Setter.Value></Setter>
</Style>

现在我们需要进行一些操作。我希望在单击[x]按钮时将选项卡项删除。双击选项卡标题时，我也想引发一个事件。此双击通知将由TabWindow使用，在那里它将生成一个新 TabWindow并将内容从单击的选项卡项移动到新窗口。基本上，这等效于将选项卡拖出到新窗口，因此双击选项卡标题可创建一个新TabWindow实例，并删除双击的选项卡项。

public override void OnApplyTemplate()
{base.OnApplyTemplate();Button closeButton = base.GetTemplateChild("tabItemCloseButton") as Button;if (closeButton != null)closeButton.Click += new System.Windows.RoutedEventHandler(closeButton_Click);Grid headerGrid = base.GetTemplateChild("gridHeader") as Grid;if (headerGrid != null)headerGrid.MouseLeftButtonDown += new MouseButtonEventHandler(headerGrid_MouseLeftButtonDown);
}void closeButton_Click(object sender, System.Windows.RoutedEventArgs e)
{var tabCtrl = this.Parent as TabControl;if (tabCtrl != null)tabCtrl.Items.Remove(this);
}void headerGrid_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{if (e.ClickCount == 2)this.RaiseEvent(new RoutedEventArgs(TabHeaderDoubleClickEvent, this));
}

派生的TabControl支持自定义选项卡之间的拖放

void DragSupportTabControl_QueryContinueDrag(object sender, QueryContinueDragEventArgs e)
{if (e.KeyStates == DragDropKeyStates.LeftMouseButton){Win32Helper.Win32Point p = new Win32Helper.Win32Point();if (Win32Helper.GetCursorPos(ref p)){Point _tabPos = this.PointToScreen(new Point(0, 0));if (!((p.X >= _tabPos.X && p.X <= (_tabPos.X + this.ActualWidth) && p.Y >= _tabPos.Y && p.Y <= (_tabPos.Y + this.ActualHeight)))){var item = e.Source as TabItem;if (item != null)UpdateWindowLocation(p.X - 50, p.Y - 10, item);}else{if (this._dragTornWin != null)UpdateWindowLocation(p.X - 50, p.Y - 10, null);}}}else if (e.KeyStates == DragDropKeyStates.None){this.QueryContinueDrag -= DragSupportTabControl_QueryContinueDrag;e.Handled = true;if (this._dragTornWin != null){_dragTornWin = null;var item = e.Source as TabItem;if (item != null)this.RemoveTabItem(item);}}
}

不幸的是，WPF没有提供可靠的方法来检索桌面屏幕上的当前鼠标位置。如果鼠标指针位于Control中，则有一种可靠的方法来获取准确的鼠标位置，但是将鼠标指针拖出控件或窗口时并非如此。无论鼠标指针在控件内还是窗口外，检索鼠标位置对我来说都是至关重要的。我的帮助来自Win32 API。

[DllImport("user32.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
internal static extern bool GetCursorPos(ref Win32Point pt);

允许将一个窗口切换到另一个窗口的TabWindow

void TabWindow_SourceInitialized(object sender, EventArgs e)
{HwndSource source = HwndSource.FromHwnd(new WindowInteropHelper(this).Handle);source.AddHook(new HwndSourceHook(WndProc));
}

因此，当窗口被标题栏抓住并拖动时，Win32消息将在钩子处理程序中接收。我们仅处理与目标相关的窗口消息。我们的目标是什么？我想在TabWindow标题栏开始拖动时得到通知。那是WM_ENTERSIZEMOVE信息。在TabWindow拖动这些对象时，需要处理窗口的坐标，这就是WM_MOVE消息。最后，WM_EXITSIZEMOVE指示拖动完成。处理这些winProc消息可以实现我们的目标。将一个 TabWindow拖到另一个TabWindow上时，将显示选项卡放置区图像。将拖动的窗口拖放到选项卡放置区域图像上，拖动的窗口将成功添加到固定窗口。

private IntPtr WndProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
{if (msg == Win32Helper.WM_ENTERSIZEMOVE)_hasFocus = true;else if (msg == Win32Helper.WM_EXITSIZEMOVE){_hasFocus = false;DragWindowManager.Instance.DragEnd(this);}else if (msg == Win32Helper.WM_MOVE){if (_hasFocus)DragWindowManager.Instance.DragMove(this);}handled = false;return IntPtr.Zero;
}

拖动的TabWindow如何判断下面的窗口是否为TabWindow类型？好了，当TabWindow实例化时，它会将自己注册到DragWindowManger单例实例。每当TabWindow移动时，它就会循环访问所有注册的窗口，以检测所拖动的鼠标位置是否在这些TabWindow实例之一上。

public void DragMove(IDragDropToTabWindow dragWin)
{if (dragWin == null) return;Win32Helper.Win32Point p = new Win32Helper.Win32Point();if (!Win32Helper.GetCursorPos(ref p)) return;Point dragWinPosition = new Point(p.X, p.Y);foreach (IDragDropToTabWindow existWin in _allWindows){if (dragWin.Equals(existWin)) continue;if (existWin.IsDragMouseOver(dragWinPosition)){if (!_dragEnteredWindows.Contains(existWin))_dragEnteredWindows.Add(existWin);}else{if (_dragEnteredWindows.Contains(existWin)){_dragEnteredWindows.Remove(existWin);existWin.OnDrageLeave();}}}
...
}

将拖动的TabWindow放到选项卡放置区域后，拖动窗口的内容将传输到在目标TabWindow上创建的新选项卡。然后拖拽的TabWindow消失了。

public void DragEnd(IDragDropToTabWindow dragWin)
{if (dragWin == null) return;Win32Helper.Win32Point p = new Win32Helper.Win32Point();if (!Win32Helper.GetCursorPos(ref p)) return;Point dragWinPosition = new Point(p.X, p.Y);foreach (IDragDropToTabWindow targetWin in _dragEnteredWindows){if (targetWin.IsDragMouseOverTabZone(dragWinPosition)){System.Windows.Controls.ItemCollection items = ((ITabWindow)dragWin).TabItems;for (int i = 0; i < items.Count; i++){System.Windows.Controls.TabItem item = items[i] as System.Windows.Controls.TabItem;if (item != null)((ITabWindow)targetWin).AddTabItem(item.Header.ToString(), (System.Windows.Controls.Control)item.Content);}for (int i = items.Count; i > 0; i--){System.Windows.Controls.TabItem item = items[i - 1] as System.Windows.Controls.TabItem;if (item != null)((ITabWindow)dragWin).RemoveTabItem(item);}}targetWin.OnDrageLeave();}if (_dragEnteredWindows.Count > 0 && ((ITabWindow)dragWin).TabItems.Count == 0){((Window)dragWin).Close();}_dragEnteredWindows.Clear();
}

总结