C# : Error while accessing Active Directory

Question

hi. i am facing some problems in accessing Active Directory from my winform app. what I want is to create a user and query user from Active Directory.

here is code snippet for find user

 public bool FindUser(string username)
        {
            using (PrincipalContext context = new PrincipalContext(ContextType.Domain, this.domainName, this.DomainUserName, this.DomainPassword))
            {                
                UserPrincipal user = UserPrincipal.FindByIdentity(context, username);
                return (user != null) ? true : false;
            }
        }

i am unable to create object of PrincipalContext based on given arguments. i am getting this exception "{"The server could not be contacted."}"

and inner exception states that "{"The LDAP server is unavailable."}"

where as domain is running. i can ping to it and can also connect to this domain.

any suggestion about these exceptions?

Answer 1

You can use the following code:

public static bool Exists(string objectPath)
{
    bool found = false;
    if (DirectoryEntry.Exists(objectPath))
    {
        found = true;
    }
    return found;
}

objectPath = "LDAP://CN=SC-5515_2,OU=Forus,DC=MyDomainName,DC=no";

This is the code i use for this. Works fine on testing if any object exists in Active directory

Answer 2

Mohsan, I know that this response is a little late, but are you still having the same problem? Are you trying to read user information, or write user information to Active Directory?

Answer 3

You can try next code.

    public bool FindUser2(string userName)
    {
        try
        {
            DirectoryContext context = new DirectoryContext(
                DirectoryContextType.Domain,
                domainName,
                domainName + @"\" + domainUserName,
                domainPassword);
            DirectoryEntry domainEntry = Domain.GetDomain(context).GetDirectoryEntry();
            DirectorySearcher searcher = new DirectorySearcher(domainEntry,
                                                               "(|(objectCategory=user)(cn=" + domainUserName + "))");
            SearchResult searchResult = searcher.FindOne();
            return searchResult != null;
        }
        catch
        {
            return false;
        }
    }

Answer 4

You can also consider using System.DirectoryServices.Protocols for accessing other domains. Bit of a steep learning curve but much faster and more flexible - e.g. you can do proper asynchronous searches.