Read (Get) Connection String from App.Config file using C# and VB.Net

Here Mudassar Ahmed Khan has explained how to use Connection String from App.Config file using C# and VB.Net by reading the value of the Connection String from the ConnectionStrings section of the App.Config. In Windows applications, Class Library or Console applications one has to reference the System.Configuration Assembly in order to read Connection String value from the App.Config file.