public void AddTabItem()

in tools/Explorer/TabControl/TabControl.cs [599:647]
37 lines of code
14 McCabe index (conditional complexity)

        public void AddTabItem()
        {
            if (IsFixedSize)
                throw new InvalidOperationException("ItemsSource is Fixed Size");

            int i = this.SelectedIndex;

            // give an opertunity to cancel the adding of the tabitem
            CancelEventArgs c = new CancelEventArgs();
            if (TabItemAdding != null)
                TabItemAdding(this, c);

            if (c.Cancel)
                return;

            TabItem tabItem;

            // Using ItemsSource property
            if (ItemsSource != null)
            {
                IList list = (IList)ItemsSource;
                NewTabItemEventArgs n = new NewTabItemEventArgs();
                if (NewTabItem == null)
                    throw new InvalidOperationException("You must implement the NewTabItem event to supply the item to be added to the tab control.");

                NewTabItem(this, n);
                if (n.Content == null)
                    return;

                if (i == -1 || i == list.Count - 1 || AddNewTabToEnd)
                    list.Add(n.Content);
                else
                    list.Insert(++i, n.Content);

                tabItem = (TabItem)this.ItemContainerGenerator.ContainerFromItem(n.Content);
            }
            else
            {
                // Using Items Property
                tabItem = new TabItem { Header = "New Tab" };
                if (i == -1 || i == this.Items.Count - 1 || AddNewTabToEnd)
                    this.Items.Add(tabItem);
                else
                    this.Items.Insert(++i, tabItem);
            }

            if (TabItemAdded != null)
                TabItemAdded(this, new TabItemEventArgs(tabItem));
        }