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:

<?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>

Can you add some code? What do you mean by it wouldn't accept the assembly? Are you getting a specific error message? — Joshua Belden
– Joshua Belden, Commented Aug 13, 2009 at 22:56

Kieran · Accepted Answer · 2018-04-23 02:08:57Z

897

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 on the References / Dependencies
Choose Add Reference
Find and add System.Configuration.

This will work for sure. Also for the NameValueCollection you have to write:

using System.Collections.Specialized;

edited Apr 23, 2018 at 2:08

answered Dec 3, 2009 at 0:43

Kieran

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6 Comments

Dhaust Over a year ago

+1 Thanks Kieran. Do you know why this has to be done when most other assemblies can simply be called by including the 'using' statement?

Kieran Over a year ago

This is my understanding: it may be wrong. When you add the reference you are asking the dll to be copied to the bin folder on compile/ build. Some dll's seen as core are added when the project is created, ie when you go file->new project so the references are set up at that point. They all have to go through the same process just that some are done for you and some you have to do manually. You could test it out by deleting the reference to your System dll and watching all your code fail. =)

Kieran Over a year ago

OK. So I have done a little more research and found that above is mostly true. However some of the files will not need to be written to the bin folder on run as they are in the Global Assembly cashe (GAC), where bin is local assembly cashe. Like the System.dll.

jaybro Over a year ago

The 'System.Configuration' namespace can be found in 'System' dll, that's why there may be some head scratching when Intellisense accepts the 'using System.Configuration;' but will not find ConfigurationManager unless the System.Configuration.dll is referenced by the project.

LordWabbit Over a year ago

Why System.Configuration is not added as a reference in the default project template I don't know? Do so few people use the configuration file that it was decided you needed to add the reference manually to stop potential unnecessary reference bloat? I just find it very annoying, every project, "Add Reference".

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David Ferenczy Rogožan · Accepted Answer · 2017-08-09 23:12:37Z

In your project, right-click, Add Reference..., in the .NET tab, find the System.Configuration component name and click OK.

using System.Configuration tells the compiler/IntelliSense to search in that namespace for any classes you use. Otherwise, you would have to use the full name (System.Configuration.ConfigurationManager) every time. But if you don't add the reference, that namespace/class will not be found anywhere.

Note that a DLL can have any namespace, so the file System.Configuration.dll could, in theory, have the namespace Some.Random.Name. For clarity/consistency they're usually the same, but there are exceptions.

pencilslate · Accepted Answer · 2009-08-14 01:43:06Z

46

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

answered Aug 14, 2009 at 1:43

pencilslate

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4 Comments

Reinstate Monica Cellio Over a year ago

Over 7 years later and it's still a shame how often this is the answer.

ggiaquin16 Over a year ago

nothing like marking your own reply as the answer, when it is indeed not the answer. Too bad mods can't edit it for the actual correct answer. Dude marked his own answer for points....

JAD Over a year ago

@ggiaquin16 you don't get the points if you accept yourself ;)

ebyrob Over a year ago

@calios or if you read the original question you can see that the questioner had already added the assembly to the project in the first version of the question. For this particular assembly and version of VS it was necessary to restart the IDE or the error would just keep happening. that was the solution. The two highly rated answers here were never relevant to the question actually being asked, but you don't think to wonder why someone would answer a question without reading it first. (in the vein of doing things just for points that does seem very effective in this case...)

WonderWorker · Accepted Answer · 2018-10-22 13:02:24Z

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.

why not use Nuget tho? Since you're likely already using Nuget to manage dependencies.

Saad Lembarki · Accepted Answer · 2019-09-23 07:48:38Z

25

Just install

Install-Package System.Configuration.ConfigurationManager -Version 4.5.0

then use

using System.Configuration;

answered Sep 23, 2019 at 7:48

Saad Lembarki

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1 Comment

oey Over a year ago

For dotnet core I had to run dotnet add package System.Configuration.ConfigurationManager in order to get this working.

Esther Lalremruati · Accepted Answer · 2017-11-09 12:20:17Z

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.

Stephen Rauch · Accepted Answer · 2018-10-06 01:08:17Z

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

now you can:

using System.Configuration;

Matt · Accepted Answer · 2016-12-20 09:16:15Z

If you're getting a lot of warnings (in my case 64 in a solution!) like

CS0618: 'ConfigurationSettings.AppSettings' is obsolete: 'This method is obsolete, it has been replaced by System.Configuration!System.Configuration.ConfigurationManager.AppSettings'

because you're upgrading an older project you can save a lot of time as follows:

Add System.Configuration as a reference to your References section.
Add the following two using statements to the top of each class (.cs) file:

using System.Configuration; using ConfigurationSettings = System.Configuration.ConfigurationManager;

By this change all occurances of

ConfigurationSettings.AppSettings["mySetting"]

will now reference the right configuration manager, no longer the deprecated one, and all the CS0618 warnings will go away immediately.

Of course, keep in mind that this is a quick hack. On the long term, you should consider refactoring the code.

Josh Gallagher · Accepted Answer · 2017-02-08 11:56:18Z

I have gotten a better solution for the issue configurationmanager does not exist in the current context.

To a read connection string from web.config we need to use ConfigurationManager class and its method. If you want to use you need to add namespace using System.Configuration;

Though you used this namespace, when you try to use the ConfigurationManager class then the system shows an error “configurationmanager does not exist in the current context”. To solve this Problem:

ConfigurationManager.ConnectionStrings["ConnectionSql"].ConnectionString;

Dan Diplo · Accepted Answer · 2009-08-13 22:05:42Z

7

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.

answered Aug 13, 2009 at 22:05

Dan Diplo

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2 Comments

pencilslate Over a year ago

Assembly details from property window: Name: System.configuration Path: C:\Windows\Microsoft.NET\Framework\v2.0.50727\System.configuration.dll Version: 2.0.0.0 Runtime Version: v2.0.50727 Anything looks suspicious? Thanks!

Dan Diplo Over a year ago

No, that is exactly as expected. How really strange - I'm sorry, but I've never seen this before. Good luck!

Mohith Maratt · Accepted Answer · 2021-08-05 19:11:45Z

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.

Nevada · Accepted Answer · 2009-08-14 00:28:43Z

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.

Steve Rey · Accepted Answer · 2011-06-03 06:37:24Z

If this code is on a separate project, like a library project. Don't forgeet to add reference to system.configuration.

Peter O. · Accepted Answer · 2012-02-28 16:24:07Z

0

You may also get this error if you add a reference to a different, unrelated project by mistake. Check if that applies to you.

edited Feb 28, 2012 at 16:24

Peter O.

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answered Feb 28, 2012 at 15:53

Ike

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Comments

Keshav Patel · Accepted Answer · 2017-08-24 10:58:34Z

To Solve this problem go to Solution Explorer And right click reference and click add reference and chose .net and find system.configuration select an click ok

shyamu · Accepted Answer · 2019-12-26 13:34:29Z

0

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

answered Dec 26, 2019 at 13:34

shyamu

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James Hirschorn · Accepted Answer · 2020-06-17 18:03:53Z

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();

...

Franz · Accepted Answer · 2020-08-08 08:59:46Z

The configuration manager of web configuration (web.config) is obsolete. So see this https://learn.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;

zalky · Accepted Answer · 2022-10-04 19:02:36Z

If you are using Entity Framework Core, an alternative solution can be as following;

Right click to project and select 'Manage Nuget Packages
On the 'Browse' tab, search for 'Z.EntityFramework.Extensions.EFCore'
Install the package, and 'using System.Configuration;' will be added automatically.

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