As we know that while interacting our SQL database to our C#.net or VB.net application we need to access the connectionstring of the SQL database. Once we access the connectionstring then we can use this to execute the SQL commands in our coding page. Now the question is when we have multiple forms in our desktop application we need to write the connectionstring on each window form to access the SQL database. So guys what to do to ignore this multiple writing of connectionstring on each form? Â To avoid this we use an app.config file into our desktop application as we use the web.config file in web application. As we describe our connectionstring once in this app.config file we can access this connectionstring multiple times on multiple forms from app.config file. in this article we will tell you the process to access this.