title: Why connection string is not found or empty
body: <p>My web.config file is this:</p>
  
  <pre><code> &lt;appSettings&gt;
      ...
      &lt;add key="gvConnString" value="user id = user1; password= pwww333; server= magcian; database= OnB; connection timeout=30" /&gt;
      ...
    &lt;/appSettings&gt;
  </code></pre>
  
  <p>In my .aspx page I use it like this:</p>
  
  <pre><code>&lt;asp:SqlDataSource ID="dsPopulateDepartment" runat="server" ConnectionString="&lt;%$ ConnectionStrings:gvConnString %&gt;" SelectCommand="SELECT * FROM HERECOMES"&gt;&lt;/asp:SqlDataSource&gt;
  </code></pre>
  
  <p>I get the following error:</p>
  
  <p><code>Exception Details: System.InvalidOperationException: The connection name 'gvConnString' was not found in the applications configuration or the connection string is empty.</code></p>