title: Can we declare variables in the 'app.config' file?
body: <p>I have a form which needs to get connected to SQL Server, and I have a drop down for selecting the list of databases and perform operations like primary key checking, etc.</p>
  
  <p>But presently my connection string looks like this:</p>
  
  <pre><code>SqlConnection sConnection = new SqlConnection("Server=192.168.10.3;DataBase=GoalPlanNew;User Id=gp;Password=gp");
  </code></pre>
  
  <p>But apart from the given database, I need to take it variable, so that I can connect it to the database I select from the dropdown.</p>
  
  <p>How can I do this?</p>