Get List of Departments from Active Directory is missing certain departments

Question

I have a method that I am using the get a list of departments in our active directory. However some (at least one that I know of) is not showing up. "EMP-Alumni Relations" is the one I am troubleshooting at the moment.

Here is the code I am using. If anyone can identify any potential problems I would appreciate it. I am at a loss for the moment. I have identified several users who are in the department so I know that should not be the issue.

ArrayList GetAdDepts (  )
    {
        DirectoryEntry myLdapConnection = SCDirectoryEntry.GetDirectoryEntry ( );
        DirectorySearcher search = new DirectorySearcher ( myLdapConnection );
        search.Filter = "(objectClass=user)";
        search.PropertiesToLoad.Add ( "department" );
        SearchResultCollection result = search.FindAll ( );
        ArrayList departments = new ArrayList ( );
        foreach ( SearchResult depart in result )
        {
            DirectoryEntry directoryEntry = depart.GetDirectoryEntry ( );

            if ( directoryEntry.Properties.Contains ( "department" ) )
            {
                string dept = ( string ) depart.Properties [ "department" ] [ 0 ];
                if ( dept.Trim ( ).StartsWith ( "EMP-" ) )
                {
                    if ( !departments.Contains ( dept ) )
                    {
                        departments.Add ( dept );
                    }
                }
            }

        }
        return departments;
    }

Answer 1

Are there more than 1000 users? If so you are probably hitting the limit described in the answer to this question.

Try setting:

search.PageSize = ... some non-zero value ...;

Also you should be disposing your disposable objects DirectorySearcher, SearchResultCollection, DirectoryEntry, with a using statement e.g.:

using (var search = new DirectorySearcher(myLdapConnection ))
{
    search.Filter = "(objectClass=user)";          
    search.PropertiesToLoad.Add ( "department" );          
    search.PageSize = 1000; // any non-zero value will work
    using (var result = search.FindAll ( ))
    {
        ...
        foreach ( SearchResult depart in result )             
        {                 
            using (var directoryEntry = depart.GetDirectoryEntry ( ))
            {
                ...
            }
        }
    }
}