ES-975464 - Resolve the ReadMe issue in this sample repository

Author: SreemonPremkumarM

README.md

@@ -1,2 +1,37 @@
-# How to load child items on demand in wpf treeview?
-This repository describes how to load child items on demand in wpf treeview
+# How to load child items on demand in WPF TreeView
+
+This repository describes how to load child items on demand in [WPF TreeView](https://www.syncfusion.com/wpf-controls/treeview) (SfTreeView).
+
+You can load child items for the node in [Execute](https://learn.microsoft.com/en-us/dotnet/api/system.windows.input.routedcommand.execute?view=netframework-4.0) method of `LoadOnDemandCommand`. Execute method will get called when user expands the tree node. In `LoadOnDemand.Execute` method, you have can perform following operations,
+
+* Show or hide busy indicator in the place of expander by setting [TreeViewNode.ShowExpanderAnimation](https://help.syncfusion.com/cr/wpf/Syncfusion.UI.Xaml.TreeView.Engine.TreeViewNode.html#Syncfusion_UI_Xaml_TreeView_Engine_TreeViewNode_ShowExpanderAnimation) until the data fetched.
+* Once data fetched, you can populate the child nodes by calling [TreeViewNode.PopulateChildNodes](https://help.syncfusion.com/cr/wpf/Syncfusion.UI.Xaml.TreeView.Engine.TreeViewNode.html#Syncfusion_UI_Xaml_TreeView_Engine_TreeViewNode_PopulateChildNodes_System_Collections_IEnumerable_) method by passing the child items collection.
+* When load on-demand command executes expanding operation will not be handled by TreeView. So, you have to set [TreeViewNode.IsExpanded](https://help.syncfusion.com/cr/wpf/Syncfusion.UI.Xaml.TreeView.Engine.TreeViewNode.html#Syncfusion_UI_Xaml_TreeView_Engine_TreeViewNode_IsExpanded) property to true to expand the tree node after populating child nodes.
+* You can skip population of child items again and again when every time the node expands, based on [TreeViewNode.ChildNodes](https://help.syncfusion.com/cr/wpf/Syncfusion.UI.Xaml.TreeView.Engine.TreeViewNode.html#Syncfusion_UI_Xaml_TreeView_Engine_TreeViewNode_ChildNodes) count.
+
+``` csharp
+/// <summary>
+/// Execute method is called when any item is requested for load-on-demand items.
+/// </summary>
+/// <param name="obj">TreeViewNode is passed as default parameter </param>
+private void ExecuteOnDemandLoading(object obj)
+{
+    var node = obj as TreeViewNode;
+
+    // Skip the repeated population of child items when every time the node expands.
+    if (node.ChildNodes.Count > 0)
+    {
+        node.IsExpanded = true;
+        return;
+    }
+
+    //Animation starts for expander to show progressing of load on demand
+    node.ShowExpanderAnimation = true;
+    var sfTreeView = Application.Current.MainWindow.FindName("sfTreeView") as SfTreeView;
+    sfTreeView.Dispatcher.BeginInvoke(DispatcherPriority.ApplicationIdle, new Action(() =>
+    {
+        currentNode = node;
+        timer.Start();
+    }));
+}
+```