How to do a "New Tab" tab

I aslo want to add + button in DockSite like google chrome.

I could not reach the answer from this discussion.

There are no ReverseMeasureDockPanel under TabbedMdiContainer.

How can I acheive the + button?

Hi Roger,

I just verified that there is a ReverseMeasureDockPanel within TabbedMdiContainer's template.  So you'd have to follow along with the thread to see what the other customers did.  Unfortunately we don't have a sample for an "add" button at this time but I will log the request for one.

Here is a sample application that shows the concept. Just create a new project in Visual Studio and paste in the following XAML and cs code. Both the Add button at the bottom and the + button at the top will add a new document.  

Here is the XAML first. 

<Window x:Class="ActiProAddTab.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:docking="http://schemas.actiprosoftware.com/winfx/xaml/docking"
        Title="MainWindow" Height="350" Width="525">
      <Grid>
         <Grid.RowDefinitions>
            <RowDefinition Height="*" />
            <RowDefinition Height="Auto" />
         </Grid.RowDefinitions>
         <DockPanel x:Name="mainDockPanel" LastChildFill="True" Grid.Row="0" Margin="0" >
            <docking:DockSite x:Name="dockSite" >
               <docking:Workspace >
                  <docking:TabbedMdiHost x:Name="tabbedMdiHost" Background="LightGray" IsCloseButtonOnTab="False">
                     <docking:TabbedMdiContainer x:Name="documentContainer" >
                     </docking:TabbedMdiContainer>
                  </docking:TabbedMdiHost>
               </docking:Workspace>
            </docking:DockSite>
         </DockPanel>
         <StackPanel Orientation="Horizontal" Grid.Row="1">
            <Button x:Name="btnAdd" Content="Add..." PreviewMouseDown="btnAdd_MouseDown" />
         </StackPanel>
      </Grid>
</Window>

 And now the code behind.

public partial class MainWindow : Window
   {
      public MainWindow()
      {
         InitializeComponent();
         this.Loaded += new RoutedEventHandler(MainWindow_Loaded);
      }

      private void MainWindow_Loaded(object sender, RoutedEventArgs e)
      {
         TextBlock text = new TextBlock();
         text.Text = "Hello, this is document number " + dockSite.DocumentWindows.Count.ToString();
         AddDocWindow(text, dockSite, "Document" + dockSite.DocumentWindows.Count.ToString());

         AddPlusButton();
      }

      public Grid CreateHeaderGrid(string strName, string strToolTip = "")
      {
         // Create the header
         Grid headerGrid = new Grid();
         headerGrid.ColumnDefinitions.Add(new ColumnDefinition());
         TextBlock titleText = new TextBlock();
         titleText.Text = strName;
         headerGrid.Children.Add(titleText);
         titleText.SetValue(Grid.ColumnProperty, 0);

         if (strToolTip != "")
         {
            TextBlock txtToolTip = new TextBlock();
            txtToolTip.Text = strToolTip;
            headerGrid.ToolTip = txtToolTip;
         }
         return (headerGrid);
      }

      private DocumentWindow AddWindow(string name, DockSite dockSite, Grid headerGrid)
      {
         var newDocWindow = new DocumentWindow(dockSite, null, name, null, null);
         newDocWindow.Header = headerGrid;
         newDocWindow.CanRaft = true;
         newDocWindow.CanClose = false;
         newDocWindow.Name = name.Replace(" ", "");
         newDocWindow.Activate();
         return newDocWindow;
      }

      public void AddDocWindow(Object control, DockSite dockSite, string name)
      {
         Grid newHeaderGrid = CreateHeaderGrid(name, "My happy tooltip");
         DocumentWindow docWin = AddWindow(name, dockSite, newHeaderGrid);
         docWin.Content = control;
      }

      private void btnAdd_MouseDown(object sender, MouseButtonEventArgs e)
      {
         TextBlock text = new TextBlock();
         text.Text = "Hello, this is document number " + dockSite.DocumentWindows.Count.ToString();
         AddDocWindow(text, dockSite, "Document" + dockSite.DocumentWindows.Count.ToString());
      }

      private void AddPlusButton()
      {
         var panels = FindVisualChildren<ReverseMeasureDockPanel>(documentContainer);

         ReverseMeasureDockPanel panel = panels.Where(r => r is FrameworkElement).First(r => (r.Parent as FrameworkElement).Name == "tabContainer");

         Button addButton = new Button();
         addButton.PreviewMouseDown += new MouseButtonEventHandler(addButton_PreviewMouseDown);
         addButton.Content = "+";
         panel.Children.Add(addButton);
         ReverseMeasureDockPanel.SetDock(addButton, Dock.Left);
      }

      private void addButton_PreviewMouseDown(object sender, MouseButtonEventArgs e)
      {
         TextBlock text = new TextBlock();
         text.Text = "Hello, this is document number " + dockSite.DocumentWindows.Count.ToString();
         AddDocWindow(text, dockSite, "Document" + dockSite.DocumentWindows.Count.ToString());
      }

      public static IEnumerable<T> FindVisualChildren<T>(DependencyObject depObj) where T : DependencyObject
      {
         if (depObj != null)
         {
            for (int i = 0; i < VisualTreeHelper.GetChildrenCount(depObj); i++)
            {
               DependencyObject child = VisualTreeHelper.GetChild(depObj, i);
               if (child != null && child is T)
               {
                  yield return (T)child;
               }

               foreach (T childOfChild in FindVisualChildren<T>(child))
               {
                  yield return childOfChild;
               }
            }
         }
      }
   }

I ran into another problem because the child of an MdiHost isn't always a TabbedMdiContainer. In this case, I search for a TabbedMdiContainer descendant. This code finds all TabbedMdiContainer descendants and I just use the first one I find.

UIElement element = mdiHost.Content as UIElement;
foreach (TabbedMdiContainer child in FindVisualChildren<TabbedMdiContainer>(element))
{