GroupPrincipal method FindByIdentity throw strange

Question

I am trying to get all users by group name and dispalay it in sharepoint webpart. adGroupName something like = "CompanyGroup".

GroupPrincipal grp = GroupPrincipal.FindByIdentity(ctx, IdentityType.Name, adGroupName);

Exception:

In order to perform this operation a successful bind must be completed on the connection

Why is that and what i am doing wrong?

stack trace:

       at System.DirectoryServices.DirectoryEntry.Bind(Boolean throwIfFail)
   at System.DirectoryServices.DirectoryEntry.Bind()
   at System.DirectoryServices.DirectoryEntry.get_AdsObject()
   at System.DirectoryServices.PropertyValueCollection.PopulateList()
   at System.DirectoryServices.PropertyValueCollection..ctor(DirectoryEntry entry, String propertyName)
   at System.DirectoryServices.PropertyCollection.get_Item(String propertyName)
   at System.DirectoryServices.AccountManagement.PrincipalContext.DoLDAPDirectoryInitNoContainer()
   at System.DirectoryServices.AccountManagement.PrincipalContext.DoDomainInit()
   at System.DirectoryServices.AccountManagement.PrincipalContext.Initialize()
   at System.DirectoryServices.AccountManagement.PrincipalContext.get_QueryCtx()
   at System.DirectoryServices.AccountManagement.Principal.FindByIdentityWithTypeHelper(PrincipalContext context, Type principalType, Nullable`1 identityType, String identityValue, DateTime refDate)
   at System.DirectoryServices.AccountManagement.Principal.FindByIdentityWithType(PrincipalContext context, Type principalType, IdentityType identityType, String identityValue)
   at System.DirectoryServices.AccountManagement.GroupPrincipal.FindByIdentity(PrincipalContext context, IdentityType identityType, String identityValue)
   at NewCo.Intranet.Common.DataAccess.ADUserManager.GetUserForGroup(String adGroupName, Boolean recursive)
   at NewCo.Intranet.Common.DataAccess.ADUserManager.GetMemberForCurrentSite()
   at NewCo.Intranet.Components.WebParts.ADGroupMembers.ADGroupMembersUserControl.Page_Load(Object sender, EventArgs e)

DirectoryServicesCOMException {"An operations error occurred.\r\n"}

Answer 1

Do you use something like this to get your context ?

/* Retreiving a principal context
*/
PrincipalContext ctx = new PrincipalContext(ContextType.Domain, "MachineIP:389", "dc=dom,dc=fr", "jpb", "root.123");

Where you can replace MachineIP by the DNS name of your domain or one of you DC.

Answer 2

Answer was found in blog:

http://sharepoint-tweaking.blogspot.com/2007/12/impersonation-in-aspnet-causes.html

Solution is to use code:

using (HostingEnvironment.Impersonate()) {
     // This code runs as the application pool user
     DirectorySearcher searcher ...
}