title: ConnectionString from app.config of a DLL is null
body: <p>I have a class library that contains a valid connectionString inside the app.config. Inside that class library I want to use it with</p>
  
  <pre><code>ConfigurationManager.ConnectionStrings["NAME"].ConnectionString
  </code></pre>
  
  <p>My ASP.net 4.0 framework application references that DDL and retrieves data from it. I want create a Entity Framework 4 DataContext within my DDL with the ConnectionString from the App.config. (I do not want to pass the connectionString from my ASP.net application in every single method. (I'm using ObjectDataSources))</p>
  
  <p>However, this line inside my DLL throws a NullReferenceException.</p>
  
  <pre><code>ConfigurationManager.ConnectionStrings["NAME"].ConnectionString
  </code></pre>
  
  <p>How can I fix this issue?</p>