Update README.md

Author: SweathaBharathi

README.md

@@ -1,4 +1,63 @@
-# How-to-bind-the-selecteditem-in-wpf-treeview-control-
-This session explains about how to bind the selecteditem in wpf treeview control?
+# How to bind the SelectedTreeItem to WPF TreeViewAdv?
 
-KB article - [How-to-bind-the-selecteditem-in-wpf-treeview-control](https://www.syncfusion.com/kb/11636/how-to-bind-the-selecteditem-to-wpf-treeview-control)
+Follow the below steps to bind the [SelectedTreeItem](https://help.syncfusion.com/cr/wpf/Syncfusion.Windows.Tools.Controls.TreeViewAdv.html#Syncfusion_Windows_Tools_Controls_TreeViewAdv_SelectedTreeItem) using MVVM in [WPF TreeViewAdv](https://help.syncfusion.com/wpf/classic/treeview/overview).
+
+**Step 1:** Create a Model class to responsible for exposing data from the ViewModel.
+
+**Step 2:** Create a view model class and add the properties to bind the values.
+
+**Step 3:** Define the TreeViewAdv  control and bind the SelectedTreeItem and ItemSource property.
+
+**Step 4:** Set the DataContext and ItemTemplate of TreeViewAdv to appear the appropriate items.
+
+```xml
+<Grid>
+    <syncfusion:TreeViewAdv x:Name="TreeViewAdv"
+                            AllowMultiSelect="True"
+                            ItemsSource="{Binding TreeItems}"
+                            SelectedTreeItem="{Binding SelectedItem, Mode=TwoWay}"
+                            Width="150"
+                            Height="150">
+        <syncfusion:TreeViewAdv.DataContext>
+            <local:ViewModel />
+        </syncfusion:TreeViewAdv.DataContext>
+        <syncfusion:TreeViewAdv.ItemTemplate>
+            <HierarchicalDataTemplate>
+                <TextBlock Text="{Binding Header}" />
+            </HierarchicalDataTemplate>
+        </syncfusion:TreeViewAdv.ItemTemplate>
+    </syncfusion:TreeViewAdv>
+</Grid>
+```
+
+```csharp
+public class ViewModel
+{
+    public ObservableCollection<Model> TreeItems { get; set; }
+    public object SelectedItem { get; set; }
+
+    public ViewModel()
+    {
+        TreeItems = PopulateData();
+        SelectedItem = TreeItems[1]; // Sets "Calendar" as the initially selected item.
+    }
+
+    private ObservableCollection<Model> PopulateData()
+    {
+        TreeItems = new ObservableCollection<Model>();
+        TreeItems.Add(new Model() { Header = "Mailbox" });
+        TreeItems.Add(new Model() { Header = "Calendar" });
+        TreeItems.Add(new Model() { Header = "Contacts" });
+        TreeItems.Add(new Model() { Header = "Drafts" });
+        TreeItems.Add(new Model() { Header = "Parent1" });
+        return TreeItems;
+    }
+}
+```
+
+```csharp
+public class Model
+{
+    public string Header { get; set; }
+}
+```