title: Get ConnectionString from app.config in c#
body: <p>I have defined my connection String in app.config file</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8" ?&gt;
  &lt;configuration&gt;
  
    &lt;connectionStrings&gt;
  
      &lt;add name="CString" 
           connectionString="Data Source=Bilal-PC;Initial Catalog=ATMSoftware;Integrated Security=False; User Id=sa; Password=123" 
           providerName="System.Data.SqlClient"/&gt;
    &lt;/connectionStrings&gt;
  &lt;/configuration&gt;
  </code></pre>
  
  <p>Now I want to get it into my C# class and I have tried all the <a href="https://stackoverflow.com/questions/8612560/fetching-connection-string-from-appconfig-file-in-c-sharp">methods</a>. but I am getting an error on configuration manager.</p>
  
  <p>Please help me.</p>