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

Author: SreemonPremkumarM

README.md

@@ -1,2 +1,27 @@
 # how_to_discard_all_changes
-This sample explains how to undo and redo all the unsaved changes in Spreadsheet
+
+This sample explains how to undo and redo all the unsaved changes in [WPF Spreadsheet](https://www.syncfusion.com/wpf-controls/spreadsheet).
+
+By default, all the unsaved changes are maintained in the `UndoStack` commands collection.  To discard all the unsaved changes programmatically, `Execute` the all commands in `UndoStack` collection. By executing the commands in `RedoStack` commands collection, all the discarded changes can be retrieved.
+
+``` c#
+//UndoAll the changes
+while (this.spreadsheetControl.HistoryManager.UndoStack.Count > 0) 
+{ 
+   var undo = this.spreadsheetControl.HistoryManager.UndoStack.Pop(); 
+   if (undo != null) 
+   { 
+        undo.Execute(Syncfusion.UI.Xaml.Spreadsheet.History.CommandMode.Undo); 
+   } 
+}
+ 
+//RedoAll the changes
+while (this.spreadsheetControl.HistoryManager.RedoStack.Count > 0) 
+{ 
+    var redo = this.spreadsheetControl.HistoryManager.RedoStack.Pop(); 
+    if (redo != null) 
+    {
+        redo.Execute(Syncfusion.UI.Xaml.Spreadsheet.History.CommandMode.Redo); 
+    }
+}
+```