The name 'ConfigurationManager' does not exist in the current context

Question

I am trying to access connectionstrings from the config file. The code is ASP.NET + C#. I have added System.Configuration to reference and also mentioned with using. But, still it wouldn't accept the assembly.

I am using VSTS 2008. Any idea what could be the reason? Another weird thing is the assembly name shown as "System.configuration", a lower case c which is not how names are displayed for other System assembleis.

Thanks!

ADDED CODE:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Configuration;

namespace Utility
{
    public class CommonVariables
    {
        public static String ConnectionString
        {
            get { return ConfigurationManager.ConnectionStrings["EmployeeEntities"].ConnectionString; }
        }  
    }  
}

Config file:

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <connectionStrings>
    <add name="qbankEntities" connectionString="metadata=res://*/qbankModel.csdl|res://*/qbankModel.ssdl|res://*/qbankModel.msl;provider=System.Data.SqlClient;provider connection string=&quot;Data Source=localhost;Initial Catalog=qbank;Persist Security Info=True;User ID=**;Password=****;MultipleActiveResultSets=True&quot;" providerName="System.Data.EntityClient" />
  </connectionStrings>
</configuration>

Answer 1

Are you sure you have added a reference to the .NET assembly and not something else? I'd remove your reference and then try re-adding it, making sure you select from the .NET tab in Visual Studio reference dialogue - the latest version should be 2.0.0.0 in GAC.

Answer 2

For a sanity check, try creating a new Web Application Project, open the code behind for the Default.aspx page. Add a line in Page_Load to access your connection string.

It should have System.Configuration added as reference by default. You should also see the using statement at the top of your code file already.

My code behind file now looks like this and compiles with no problems.

using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;

namespace WebApplication1
{
  public partial class _Default : System.Web.UI.Page
  {
    protected void Page_Load(object sender, EventArgs e)
    {
      string connString = ConfigurationManager.ConnectionStrings["MyConnectionStringName"].ConnectionString;
    }
  }
}

This assumes I have a connection string in my web.config with a name equal to "MyConnectionStringName" like so...

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
    <configSections>
    </configSections>
    <connectionStrings>
        <add name="MyConnectionStringName"
            connectionString="Data Source=.;Initial Catalog=MyDatabase;Integrated Security=True"
            providerName="System.Data.SqlClient" />
    </connectionStrings>
</configuration>

Yeah, it's elementary I know. But if you don't have any better ideas sometimes it helps to check against something really simple that you know should work.

Answer 3

Ok.. it worked after restarting the VSTS. The link suggested the solution for the same problem. Wish i could have seen it before. :)

Answer 4

It's not only necessary to use the namespace System.Configuration. You have also to add the reference to the assembly System.Configuration.dll , by right-click-ing on the References tab, choose add reference and then find System.Configuration. This will work for sure. Also for the NameValueCollection you have to write: using System.Collections.Specialized;