title: How to fix "the name configurationmanager does not exist in the current context"
body: <p>I already added the reference System.Configuration and still, I get recieving that error.
  I am using VS2010. Here is the code </p>
  
  <pre><code>&lt;configuration&gt;
  &lt;connectionStrings&gt;
      &lt;add name="MESConnection" connectionString="Server=.\SQLEXPRESS;Database=MES;Trusted_Connection=true"/&gt;
  &lt;/connectionStrings&gt;
  &lt;system.web&gt;
      &lt;compilation debug="true" targetFramework="4.0"&gt;
          &lt;assemblies&gt;
              &lt;add assembly="System.Configuration.Install, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B03F5F7F11D50A3A"/&gt;&lt;/assemblies&gt;&lt;/compilation&gt;
  &lt;/system.web&gt;
  </code></pre>
  
  <p></p>
  
  <p>and the code behind: </p>
  
  <pre><code>private static string _connStr = ConfigurationManager.ConnectionStrings["MESConnection"].ConnectionString;
  </code></pre>
  
  <p>Any ideas?</p>