Added basic use cases and new article

docfx/articles/treeview.md

@@ -0,0 +1,105 @@
+# Tree View
+
+TreeView is a control for navigating hierarchical objects.  It comes in two forms `TreeView` and `TreeView<T>`.  
+
+## TreeView
+
+The basic non generic TreeView class is populated by `ITreeNode` objects.  The simplest tree you can make would look something like:
+
+
+```csharp
+var tree = new TreeView()
+{
+    X = 0,
+    Y = 0,
+    Width = 40,
+    Height = 20
+};
+
+Win.Add(tree);
+
+var root1 = new TreeNode("Root1");
+root1.Children.Add(new TreeNode("Child1.1"));
+root1.Children.Add(new TreeNode("Child1.2"));
+
+var root2 = new TreeNode("Root2");
+root2.Children.Add(new TreeNode("Child2.1"));
+root2.Children.Add(new TreeNode("Child2.2"));
+
+tree.AddObject(root1);
+tree.AddObject(root2);
+
+```
+
+Having to create a bunch of TreeNode objects can be a pain especially if you already have your own objects e.g. `House`, `Room` etc.  There are two ways to use your own classes without having to create nodes manually.  Firstly you can implement the `ITreeNode` interface:
+
+
+```
+// Your data class
+private class House : ITreeNode {
+
+
+    // Your properties
+    public string Address {get;set;}
+    public List<Room> Rooms {get;set;}
+
+    // ITreeNode member:
+
+    public IList<ITreeNode> Children => Rooms.Cast<ITreeNode>().ToList();
+    
+    public override string ToString ()
+    {
+        return Address;
+    }
+}
+
+// Your other data class
+private class Room : ITreeNode{
+    
+    public string Name {get;set;}
+
+
+    // Rooms have no sub objects
+    public IList<ITreeNode> Children => new List<ITreeNode>();
+
+    public override string ToString ()
+    {
+        return Name;
+    }
+}
+
+
+...
+
+// After implementing the interface you can add your objects directly to the tree
+
+var myHouse = new House()
+{
+    Address = "23 Nowhere Street",
+    Rooms = new List<Room>{
+        new Room(){Name = "Ballroom"},
+        new Room(){Name = "Bedroom 1"},
+        new Room(){Name = "Bedroom 2"}
+    }
+};
+
+var tree = new TreeView()
+{
+    X = 0,
+    Y = 0,
+    Width = 40,
+    Height = 20
+};
+
+tree.AddObject(myHouse);
+
+
+```
+
+Alternatively you can simply tell the tree how the objects relate to one another by implementing `ITreeBuilder`.  This is a good option if you don't have control of the data objects you are working with:
+
+```
+TODO
+```
+
+## TreeView<T>