Excel Onchanged Event keeps getting called

I am writing to excel file. I am raising a event whenever the excel file changes.

private void FileChanged()
       {

           watcher.Path = DirectoryPath;
           watcher.Filter = "*.xlsx";
           watcher.NotifyFilter = NotifyFilters.FileName | NotifyFilters.LastWrite;

           watcher.Changed += new FileSystemEventHandler(OnChanged);
           watcher.EnableRaisingEvents = true;

       }

I am expecting the OnChanged method would be called when I Open the file for writing but I am seeing the OnChanged method keeps getting called several times.

In the OnChanged method I am not doing anything if it is the same process. Only if it is a different process then I am reading from excel file.

Your help is appreciated.

Tags: C#, Microsoft Excel