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 assemblies.

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:

user_5720406 · Answer

Adding the System.Configuration as reference to all the projects will solve this.

Go to Project -> Add Reference
In the box that appears, click the All assemblies list tab in the left hand list.
In the central list, scroll to System.Configuration and make sure the box is checked.
Click ok to apply, and you'll now be able to access the ConfigurationManager class.

user_7728706 · Answer

Just install

Install-Package System.Configuration.ConfigurationManager -Version 4.5.0

then use

using System.Configuration;

user_7429004 · Answer

Adding this answer, as none of the suggested solutions works for me.

Right-click on references tab to add reference.

Click on Assemblies tab

Search for 'System.Configuration'

Click OK.

user_4438070 · Answer

Right-click on Project
Select Manager NuGet Package
Find System.Configuration
Select System.Configuration.ConfigurationManager by Microsoft
Install

now you can:

using System.Configuration;

user_4977531 · Answer

For Visual Studio 2019

Right click on project and go to Manage NuGet Packages.

Search for System.Configuraion and install System.Configuration.ConfigurationManager

Now in your code, configuration manager will be recognized.

user_5850243 · Answer

Add the configuration manager file to connect to the database web.config

user_1349673 · Answer

In NetCore 3.1 I had to use Microsoft.Extensions.Configuration instead:

    public static async Task Main(string[] args)
    {
        var configuration = new ConfigurationBuilder()
            .SetBasePath(Directory.GetCurrentDirectory())
            .AddJsonFile(path: "appsettings.json", optional: false, reloadOnChange: true)
            .Build();

...

user_5531903 · Answer

The configuration manager of web configuration (web.config) is obsolete. So see this https://docs.microsoft.com/en-us/dotnet/api/system.configuration.configurationmanager.appsettings?redirectedfrom=MSDN&view=dotnet-plat-ext-3.1#System_Configuration_ConfigurationManager_AppSettings

create a instance of settings

var appSettings = ConfigurationManager.AppSettings;

create a instance of settings

var appSettings = ConfigurationManager.AppSettings;

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

18 Answers