Merge pull request #2 from SyncfusionExamples/SweathaBharathi-patch-1

Update README.md

Author: vijayarasan

README.md

@@ -1,2 +1,96 @@
 # How to save and load the tree node in a collapsed or an expanded state in WinForms TreeViewAdv?
-This example illustrates how to save and load the tree node in a collapsed or an expanded state in WinForms TreeViewAdv.
+
+In [WinForms TreeViewAdv](https://www.syncfusion.com/winforms-ui-controls/treeview) does not have support for saving its TreeNodeAdvCollection in an expanded or a collapsed state. This requirement can be achieved by the following steps.​
+
+1. Save the Expanded or Collapsed state of each of its TreeNodeAdvCollection to a Dictionary.
+2. Reload the saved state based on user requirement.
+
+**C#**
+
+```csharp
+//Initializes the collection
+Dictionary<string, bool> dic = new Dictionary<string, bool>();
+
+//Saves the Tree State
+dic = SaveTreeState(this.treeViewAdv1);
+
+//Loads the Tree state
+this.RestoreTreeState(this.treeViewAdv1, dic);
+
+//Saves TreeViewAdv
+public Dictionary<string, bool> SaveTreeState(TreeViewAdv tree)
+{
+    Dictionary<string, bool> nodeStates = new Dictionary<string, bool>();  
+    foreach (TreeNodeAdv node in Collect(tree.Nodes))
+    {
+        nodeStates.Add(node.Text,node.Expanded);
+    }
+    return nodeStates;
+}
+
+//Loads TreeViewAdv
+private void RestoreTreeState(TreeViewAdv tree, Dictionary<string, bool> treeState)
+{
+    foreach (TreeNodeAdv node in Collect(tree.Nodes))
+    {
+        if (treeState.Keys.Count != 0 && treeState[node.Text])
+            node.Expand();
+        else
+            node.Expanded = false;
+    }
+}
+
+//Iterates through all the nodes in TreeViewAdv
+IEnumerable<TreeNodeAdv> Collect(TreeNodeAdvCollection nodes)
+{
+    foreach(TreeNodeAdv node in nodes)
+    {
+        yield return node;
+        foreach (TreeNodeAdv child in Collect(node.Nodes))
+        yield return child;
+    }
+}
+```
+
+**VB.Net**
+
+```vbnet
+'Initializes the collection
+Private dic As New Dictionary(Of String, Boolean)()
+
+'Saves the Tree State
+dic = SaveTreeState(Me.treeViewAdv1)
+
+'Loads the Tree state
+Me.RestoreTreeState(Me.treeViewAdv1, dic)
+
+'Saves TreeViewAdv.
+Public Function SaveTreeState(ByVal tree As TreeViewAdv) As Dictionary(Of String, Boolean)
+   Dim nodeStates As New Dictionary(Of String, Boolean)()
+   For Each node As TreeNodeAdv In Collect(tree.Nodes)
+      nodeStates.Add(node.Text, node.Expanded)
+   Next node
+   Return nodeStates
+End Function
+
+'Loads TreeViewAdv
+Private Sub RestoreTreeState(ByVal tree As TreeViewAdv, ByVal treeState As Dictionary(Of String, Boolean))
+    For Each node As TreeNodeAdv In Collect(tree.Nodes)
+        If treeState.Keys.Count <> 0 AndAlso treeState(node.Text) Then
+ node.Expand()
+        Else
+ node.Expanded = False
+        End If
+    Next node
+End Sub
+
+'Iterates through all the nodes in TreeViewAdv
+Private Function Collect(ByVal nodes As TreeNodeAdvCollection) As IEnumerable(Of TreeNodeAdv)
+   For Each node As TreeNodeAdv In nodes
+       Return node
+       For Each child As TreeNodeAdv In Collect(node.Nodes)
+           Return child
+       Next child
+  Next node
+End Function
+```