title: Point connectionstring in dbml to app.config
body: <p>Can I just point the connection string in <code>Dbml.designer.cs</code> to the connectionstring in the <code>app.conf</code>? I wrote the code below which it successfully point to the <code>app.config</code>.</p>
  
  <pre><code>public leDataContext() : 
      base(ConfigurationManager.ConnectionStrings["leConnString"].ToString(), mappingSource)
      {
          OnCreated();
      }
  </code></pre>
  
  <p>However whenever i modify or add a table into the dbml, it will start to auto replace that code into this </p>
  
  <pre><code> public leDataContext() : 
              base("Data Source=.\\SQLEXPRESS;AttachDbFilename=\"D:\\My Projects\\App_Data\\le.mdf\";Integrated Security=True;Connect Timeout=30;User Instance=True", mappingSource)
      {
          OnCreated();
      }
  </code></pre>
  
  <p>I have expanded the "Connection" option. Set "Application Settings" to False</p>