A TreeView is used to represent data in a hierarchical fashion .It is often used to show  parent child relationship where a parent node can be expanded or collapsed.

The TreeView tag is used to create  a WPF TreeView control in XAML.

<TreeView></TreeView>

We can further set Name  property to uniquely identify the control. For setting the size of control we need to use Width and Height.

<TreeView  Name="TreeView1" Width="100" Height="200" />

A TreeView is a collection of TreeViewItems. The following markup adds a parent item and four child items to a TreeView control.

<TreeView Margin="10,10,0,13" Name="TreeView1"  Width="100" Height="200">
    <TreeViewItem Header="Technologies">
        <TreeViewItem Header="Asp.Net"></TreeViewItem>
        <TreeViewItem Header="Java"></TreeViewItem>
        <TreeViewItem Header="PHP"></TreeViewItem>
        <TreeViewItem Header="NodeJS"></TreeViewItem>       
    </TreeViewItem>
</TreeView>

We can also create a treeview dynamically as follows. For each item, we set the Header, and use a string array for the sub-items.

<TreeView Name="tView"></TreeView>
TreeViewItem treeItem = null;

// India
treeItem = new TreeViewItem();
treeItem.Header = "India";

treeItem.Items.Add(new TreeViewItem() { Header = "Delhi" });
treeItem.Items.Add(new TreeViewItem() { Header = "Mumbai" });
tView.Items.Add(treeItem);

For deleting items from TreeView we need to use the following  code:

   tView.Items.RemoveAt(tView.Items.IndexOf(tView.SelectedItem));  

In case we need to apply styles to  TreeView we use System.Resources  wherein we set the style property. Here we have set the background and font size.

<Window.Resources>
    <Style TargetType="{x:Type TreeViewItem}">                  
        <Setter Property="FontSize" Value="16"/
        <Setter Property="Background" Value="Blue"/> 
    </Style>
</Window.Resources>

The tree view control provides  lots of advanced capabilities. In this blog we have only gone through the basic concepts. Hope the article helps you in getting started on using a very important control. Do check out the official documentation for further details:

https://msdn.microsoft.com/en-us/library/system.windows.controls.treeview(v=vs.110).aspx