Eigenschaften mit Value null

Question

Hallo zusammne

Habe folgendes Problem.

Meine Properties SearchedObjClass ,SearchedProp ,SearchedPropValue in dem folgenden "Filter" 

search.Filter = string.Format("(&(ObjectClass={0})({1}={2}))",
                _searchedObjClass, _searchedProp, searchedPropValue);

sind null Value obwohl die Value im main program zugewisen sind.

Please help...Was könnte da Problem sein...

class ADClassNew
    {
 public string SearchedObjClass { get; set; }
        public string SearchedProp { get; set; }
        public string SearchedPropValue { get; set; }
  public string LdapPath { get; set; }
        
        public static DirectoryEntry createDirectoryEntry()
        {
            
            using (DirectoryEntry root =new DirectoryEntry())
            {
                root.Path = LdapPath;
                root.Username = LdapUserName;
                root.Password = LdapUserPass;
                root.AuthenticationType = AuthenticationTypes.Secure;
                return root;
            }
            
           
         }

        public static SearchResult searchDirectory()
        {
            DirectoryEntry searchEntry = ADClassNew.createDirectoryEntry();
            DirectorySearcher search = new DirectorySearcher(searchEntry);
           string _searchedObjClass = ADClassNew.SearchedObjClass;
           string _searchedProp = ADClassNew.SearchedProp;
           string searchedPropValue = ADClassNew.SearchedPropValue;

           search.Filter = string.Format("(&(ObjectClass={0})({1}={2}))", _searchedObjClass, _searchedProp, searchedPropValue);
           search.PropertiesToLoad.Add("Displayname");
            SearchResult result = search.FindOne();
           return result;
        }
 
    }
 

namespace ADSearche
{
    public partial class Form1 : Form
    {
               

        
        public Form1()
        {
            InitializeComponent();
                       

            ADClassNew adclassnew = new ADClassNew();
            adclassnew.LdapPath = "LDAP://mydomain";
            adclassnew.SearchedObjClass = "User";
            adclassnew.SearchedProp = "Displayname";
            adclassnew.SearchedPropValue = "administrator";
        }
   }
}