System.DirectoryServices is not recognised in the namespace 'System'

Question

I'm trying to use System.DirectoryServices in a web site project and I'm getting this error:

The type or namespace name 'DirectoryServices' does not exist in the namespace 'System' (are you missing an assembly reference?)

My project has a reference to System.DirectoryServices in web.config:

<add assembly="System.DirectoryServices, Version=2.0.0.0, Culture=neutral, PublicKeyToken=B03F5F7F11D50A3A"/>

And I do have using System.DirectoryServices in the files where I want to use it.

Does anybody have a clue where to look for the problem?

score 113 · Answer 1 · edited Feb 29 '16 at 00:41

113

Right click on References under your solution.
Select Add Reference. The reference can be found under the Framework Assemblies list. Select System.DirectoryServices and click Add.

edited Feb 29 '16 at 00:41

SunsetQuest

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answered Jan 03 '13 at 22:40

user1947015

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I have it in the References and it still gives me the same error as above. – vapcguy Nov 06 '14 at 23:12
3

@vapcguy Old comment but you probably need to add the Reference *System.DirectoryServices.AccountManagement* as well. – TylerH Feb 01 '18 at 20:55
why cant i find System.DirectoryServices in the reference Manager? – Lion Hunter Sep 23 '20 at 16:24

score 10 · Answer 2 · edited May 03 '18 at 19:10

10

I think you should install Directory Services Package.

Install-Package System.DirectoryServices -Version 4.0.0

Directory Services Package

edited May 03 '18 at 19:10

Vadim Ovchinnikov

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answered Sep 12 '17 at 15:21

Basma Elshoky

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score 8 · Answer 3 · edited May 03 '18 at 19:09

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Shot in the dark: have you tried adding to the web.config:

<compilation debug="true">
     <assemblies>
          <add assembly="System.DirectoryServices, Version=2.0.0.0, Culture=neutral, PublicKeyToken=B03F5F7F11D50A3A"/>
     </assemblies>
</compilation>

edited May 03 '18 at 19:09

Vadim Ovchinnikov

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answered Nov 05 '08 at 13:28

Mitch Wheat

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what about any assemblies that System.DirectoryServices is dependent upon? – Mitch Wheat Nov 05 '08 at 13:42
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The PublicKeyToken might need to be lower case, I think it might be case-sensitive -- I didn't have this line, and I just added it, with a copy/paste of the PublicKeyToken from the properties of my DLL in C:\Windows\Assembly (aka GAC) and that's what solved it, for me. – vapcguy Nov 06 '14 at 23:24
Even after adding the necessary references when I build the solution it got succesfully build and when I ran the project then I got the error as _CS0234: The type or namespace name 'DirectoryServices' does not exist in the namespace 'System' (are you missing an assembly reference?)_ I didnt got why I got the error again after successsful build – Nad Mar 16 '17 at 07:03

score 7 · Accepted Answer · answered Nov 05 '08 at 13:46

Is the web-server (IIS or whatever) configured to run the folder as an application (i.e. shows as a cog), and is it using the correct version of ASP.NET? If it is running as 1.1, bits of it might work - but it would fail to find that 2.0 assembly in the 1.1 GAC.

score 7 · Answer 5 · answered Feb 08 '12 at 16:12

7

This is a very old thread but just to provide a complete answer for the sake of posterity ;)

This issue occurs if the project is missing a reference to the .Net Component System.DirectoryServices

Adding this reference in the usual manner prefered by you will resolve the issue.

answered Feb 08 '12 at 16:12

Salman Siddiqui

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It was a web site project and I did have the assembly referenced in web.config as you can see in the question. – jansokoly Feb 09 '12 at 17:34
I've ran into the same issue and I, too, have it in the references. – vapcguy Nov 06 '14 at 23:12

score 1 · Answer 6 · answered Jun 16 '13 at 01:41

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On Solution Explorer right-click your project, then from the resulting menu, click on Add Reference, then under the .NET tab navigate to DirectoryServices.AccountManagement

answered Jun 16 '13 at 01:41

Ntsikelelo Ndleleni

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score 1 · Answer 7 · answered Nov 05 '08 at 13:19

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Is this a web site project, or a web application project. With the latter, references are handled via the .csproj - i.e. via the "References" node in Solution Explorer.

answered Nov 05 '08 at 13:19

Marc Gravell

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score 1 · Answer 8 · edited Mar 05 '19 at 10:53

These problems occur when you are working with older .net version and trying to build with the latest IDE

It depends on which version of IDE you are using and also the current code version.

Check the web config,

In my case, I was using the Latest version i.e 4.7 and directoryService assembly are still referring to C#4.0.

Add below if you are using Latest version of id i.e 4.7

  <system.web>
  <location>

<compilation debug="false" numRecompilesBeforeAppRestart="100" targetFramework="4.7">
        <assemblies>
<add assembly="System.DirectoryServices, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B03F5F7F11D50A3A" />
<add assembly="System.DirectoryServices.AccountManagement, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089" />
 </assemblies>
      </compilation>
</system.web>
  </location>

score 0 · Answer 9 · edited May 03 '18 at 19:12

I had the same problem when I tried to convert website to web-app. It looks like vs failing to load the assembly should be related to versioning. switch to web.config and add the assembly to it as bellow. make sure the DLL version is matching your application targeted .NET version.

<configuration>
  <system.web>
    <compilation debug="true" targetFramework="4.0">
      <assemblies>
        <add assembly="System.DirectoryServices, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a"/>
      </assemblies>
    </compilation>
  </system.web>
</configuration>

for getting a public key you need to launch Developer Command Prompt for VS. Change to GAC directory related framework on above ex C:\Windows\Microsoft.NET\Framework\v4.0.30319 and call

sn -T System.DirectoryServices.dll

System.DirectoryServices is not recognised in the namespace 'System'

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