I am using the System.DirectoryServices in my user control web part but when I drag anddrop the web part on page it gives the following error :its dependencies. The type or namespace name 'DirectoryServices' does notexist in the namespace 'System' (are you missing an assembly reference?)”The System.DirectoryServices is in GAC.How to solve it ?

In Visual Studio click on References->Add References and choose DirectoryServices from the .Net list

Hai Already i added directory service dll .But still i am getting the same error

Hai I am using this both System.DirectoryService version 2.0.0.0 and System.directoryService.AccountManagement version 3.5.0.0 . in my user control webpart. These versions are compatible or not?