private static IdentityImpersonation impersonate = new IdentityImpersonation(ADUser, ADPassword, DomainName);
              DirectoryEntry entry = new DirectoryEntry(ADPath, ADUser, ADPassword, AuthenticationTypes.Secure);
         private static DirectoryEntry GetDirectoryObject(string userName, string password)
              DirectoryEntry entry = new DirectoryEntry(ADPath, userName, password, AuthenticationTypes.None);
         /// i.e. /CN=Users,DC=creditsights, DC=cyberelves, DC=Com
         private static DirectoryEntry GetDirectoryObject(string domainReference)
              DirectoryEntry entry = new DirectoryEntry(ADPath + domainReference, ADUser, ADPassword, AuthenticationTypes.Secure);
         private static DirectoryEntry GetDirectoryObject(string domainReference, string userName, string password)
              DirectoryEntry entry = new DirectoryEntry(ADPath + domainReference, userName, password, AuthenticationTypes.Secure);
用户公共名称
         ///如果找到该用户,则返回用户的 对象;否则返回 null
         public static DirectoryEntry GetDirectoryEntry(string commonName)
         {
              DirectoryEntry de = GetDirectoryObject();
              DirectorySearcher deSearch = new DirectorySearcher(de);
              deSearch.Filter = "(&(&(objectCategory=person)(objectClass=user))(cn=" + commonName + "))";
              deSearch.SearchScope = SearchScope.Subtree;
 
              try
              {
                   SearchResult result = deSearch.FindOne();
                   de = new DirectoryEntry(result.Path);
                   return de;
              }
              catch
              {
                   return null;
              }
         }
 
         ///
         ///根据用户公共名称和密码取得用户的 对象。
         ///
         ///
用户公共名称
         ///
用户密码
         ///如果找到该用户,则返回用户的 对象;否则返回 null
         public static DirectoryEntry GetDirectoryEntry(string commonName, string password)
         {
              DirectoryEntry de = GetDirectoryObject(commonName, password);
              DirectorySearcher deSearch = new DirectorySearcher(de);
              deSearch.Filter = "(&(&(objectCategory=person)(objectClass=user))(cn=" + commonName + "))";
              deSearch.SearchScope = SearchScope.Subtree;
 
              try
              {
                   SearchResult result = deSearch.FindOne();
                   de = new DirectoryEntry(result.Path);
                   return de;
              }
              catch
              {
                   return null;
              }
         }
 
         ///
         ///根据用户帐号称取得用户的 对象
         ///
         ///
用户帐号名
         ///如果找到该用户,则返回用户的 对象;否则返回 null
         public static DirectoryEntry GetDirectoryEntryByAccount(string sAMAccountName)
         {
              DirectoryEntry de = GetDirectoryObject();
              DirectorySearcher deSearch = new DirectorySearcher(de);
              deSearch.Filter = "(&(&(objectCategory=person)(objectClass=user))(sAMAccountName=" + sAMAccountName + "))";
              deSearch.SearchScope = SearchScope.Subtree;
 
              try
              {
                   SearchResult result = deSearch.FindOne();
                   de = new DirectoryEntry(result.Path);
                   return de;
              }
              catch
              {
                   return null;
              }
         }
 
         ///
         ///根据用户帐号和密码取得用户的 对象
         ///
         ///
用户帐号名
         ///
用户密码
         ///如果找到该用户,则返回用户的 对象;否则返回 null
         public static DirectoryEntry GetDirectoryEntryByAccount(string sAMAccountName, string password)
         {
              DirectoryEntry de = GetDirectoryEntryByAccount(sAMAccountName);
              if (de != null)
              {
                   string commonName = de.Properties["cn"][0].ToString();
 
                   if (GetDirectoryEntry(commonName, password) != null)
                       return GetDirectoryEntry(commonName, password);
                   else
                       return null;
              }
              else
              {
                   return null;
              }
         }
 
         ///
         ///根据组名取得用户组的 对象
         ///
         ///
组名
         ///
         public static DirectoryEntry GetDirectoryEntryOfGroup(string groupName)
         {
              DirectoryEntry de = GetDirectoryObject();
              DirectorySearcher deSearch = new DirectorySearcher(de);
              deSearch.Filter = "(&(objectClass=group)(cn=" + groupName + "))";
              deSearch.SearchScope = SearchScope.Subtree;
 
              try
              {
                   SearchResult result = deSearch.FindOne();
                   de = new DirectoryEntry(result.Path);
                   return de;
              }
              catch
              {
                   return null;
              }
         }
 
         #endregion
 
         #region GetProperty
 
         ///
         ///获得指定 指定属性名对应的值
         ///
         ///
         ///
属性名称
         ///属性值
         public static string GetProperty(DirectoryEntry de, string propertyName)
         {
              if(de.Properties.Contains(propertyName))
              {
                   return de.Properties[propertyName][0].ToString() ;
              }
              else
              {
                   return string.Empty;
              }
         }
 
         ///
         ///获得指定搜索结果 中指定属性名对应的值
         ///
         ///
         ///
属性名称
         ///属性值
         public static string GetProperty(SearchResult searchResult, string propertyName)
         {
              if(searchResult.Properties.Contains(propertyName))
              {
                   return searchResult.Properties[propertyName][0].ToString() ;
              }
              else
              {
                   return string.Empty;
              }
         }
 
         #endregion
 
         ///
         ///设置指定 的属性值
         ///
         ///
         ///
属性名称
         ///
属性值
         public static void SetProperty(DirectoryEntry de, string propertyName, string propertyValue)
         {
              if(propertyValue != string.Empty || propertyValue != "" || propertyValue != null)
              {
                   if(de.Properties.Contains(propertyName))
                   {
                       de.Properties[propertyName][0] = propertyValue;
                   }
                   else
                   {
                       de.Properties[propertyName].Add(propertyValue);
                   }
              }
         }
 
         ///
         ///创建新的用户
         ///
         ///
DN 位置。例如:OU=共享平台 或 CN=Users
         ///
公共名称
         ///
帐号
         ///
密码
         ///
         public static DirectoryEntry CreateNewUser(string ldapDN, string commonName, string sAMAccountName, string password)
         {
              DirectoryEntry entry = GetDirectoryObject();
              DirectoryEntry subEntry = entry.Children.Find(ldapDN);
              DirectoryEntry deUser = subEntry.Children.Add("CN=" + commonName, "user");
              deUser.Properties["sAMAccountName"].Value = sAMAccountName;
              deUser.CommitChanges();
              ADHelper.EnableUser(commonName);
              ADHelper.SetPassword(commonName, password);
              deUser.Close();
              return deUser;
         }
 
         ///
         ///创建新的用户。默认创建在 Users 单元下。
         ///
         ///
公共名称
         ///
帐号
         ///
密码
         ///
         public static DirectoryEntry CreateNewUser(string commonName, string sAMAccountName, string password)
         {
              return CreateNewUser("CN=Users", commonName, sAMAccountName, password);
         }
 
         ///
         ///判断指定公共名称的用户是否存在
         ///
         ///
用户公共名称
         ///如果存在,返回 true;否则返回 false
         public static bool IsUserExists(string commonName)
         {
              DirectoryEntry de = GetDirectoryObject();
              DirectorySearcher deSearch = new DirectorySearcher(de);
              deSearch.Filter = "(&(&(objectCategory=person)(objectClass=user))(cn=" + commonName + "))";       // LDAP 查询串
              SearchResultCollection results = deSearch.FindAll();
 
              if (results.Count == 0)
                   return false;
              else
                   return true;
         }
 
         ///
         ///判断用户帐号是否激活
         ///
         ///
用户帐号属性控制器
         ///如果用户帐号已经激活,返回 true;否则返回 false
         public static bool IsAccountActive(int userAccountControl)
         {
              int userAccountControl_Disabled = Convert.ToInt32(ADS_USER_FLAG_ENUM.ADS_UF_ACCOUNTDISABLE);
              int flagExists = userAccountControl & userAccountControl_Disabled;
 
              if (flagExists > 0)
                   return false;
              else
                   return true;
         }
 
         ///
         ///判断用户与密码是否足够以满足身份验证进而登录
         ///
         ///
用户公共名称
         ///
密码
         ///如能可正常登录,则返回 true;否则返回 false
         public static LoginResult Login(string commonName, string password)
         {
              DirectoryEntry de = GetDirectoryEntry(commonName);
 
              if (de != null)
              {
                   // 必须在判断用户密码正确前,对帐号激活属性进行判断;否则将出现异常。
                   int userAccountControl = Convert.ToInt32(de.Properties["userAccountControl"][0]);
                   de.Close();
 
                   if (!IsAccountActive(userAccountControl))
                       return LoginResult.LOGIN_USER_ACCOUNT_INACTIVE;
 
                   if (GetDirectoryEntry(commonName, password) != null)
                       return LoginResult.LOGIN_USER_OK;
                   else
                       return LoginResult.LOGIN_USER_PASSWORD_INCORRECT;
              }
              else
              {
                   return LoginResult.LOGIN_USER_DOESNT_EXIST;
              }
         }
 
         ///
         ///判断用户帐号与密码是否足够以满足身份验证进而登录
         ///
         ///
用户帐号
         ///
密码
         ///如能可正常登录,则返回 true;否则返回 false
         public static LoginResult LoginByAccount(string sAMAccountName, string password)
         {
              DirectoryEntry de = GetDirectoryEntryByAccount(sAMAccountName);
                  
              if (de != null)
              {
                   // 必须在判断用户密码正确前,对帐号激活属性进行判断;否则将出现异常。
                   int userAccountControl = Convert.ToInt32(de.Properties["userAccountControl"][0]);
                   de.Close();
 
                   if (!IsAccountActive(userAccountControl))
                       return LoginResult.LOGIN_USER_ACCOUNT_INACTIVE;
 
                   if (GetDirectoryEntryByAccount(sAMAccountName, password) != null)
                       return LoginResult.LOGIN_USER_OK;
                   else
                       return LoginResult.LOGIN_USER_PASSWORD_INCORRECT;
              }
              else
              {
                   return LoginResult.LOGIN_USER_DOESNT_EXIST;
              }
         }
 
         ///
         ///设置用户密码,管理员可以通过它来修改指定用户的密码。
         ///
         ///
用户公共名称
         ///
用户新密码
         public static void SetPassword(string commonName, string newPassword)
         {
              DirectoryEntry de = GetDirectoryEntry(commonName);
             
              // 模拟超级管理员,以达到有权限修改用户密码
              impersonate.BeginImpersonate();
              de.Invoke("SetPassword", new object[]{newPassword});
              impersonate.StopImpersonate();
 
              de.Close();
         }
 
         ///
         ///设置帐号密码,管理员可以通过它来修改指定帐号的密码。
         ///
         ///
用户帐号
         ///
用户新密码
         public static void SetPasswordByAccount(string sAMAccountName, string newPassword)
         {
              DirectoryEntry de = GetDirectoryEntryByAccount(sAMAccountName);
 
              // 模拟超级管理员,以达到有权限修改用户密码
              IdentityImpersonation impersonate = new IdentityImpersonation(ADUser, ADPassword, DomainName);
              impersonate.BeginImpersonate();
              de.Invoke("SetPassword", new object[]{newPassword});
              impersonate.StopImpersonate();
 
              de.Close();
         }
 
         ///
         ///修改用户密码
         ///
         ///
用户公共名称
         ///
旧密码
         ///
新密码
         public static void ChangeUserPassword (string commonName, string oldPassword, string newPassword)
         {
              // to-do: 需要解决密码策略问题
              DirectoryEntry oUser = GetDirectoryEntry(commonName);
              oUser.Invoke("ChangePassword", new Object[]{oldPassword, newPassword});
              oUser.Close();
         }
 
         ///
         ///启用指定公共名称的用户
         ///
         ///
用户公共名称
         public static void EnableUser(string commonName)
         {
              EnableUser(GetDirectoryEntry(commonName));
         }
 
         ///
         ///启用指定 的用户
         ///
         ///
         public static void EnableUser(DirectoryEntry de)
         {
              impersonate.BeginImpersonate();
              de.Properties["userAccountControl"][0] = ADHelper.ADS_USER_FLAG_ENUM.ADS_UF_NORMAL_ACCOUNT | ADHelper.ADS_USER_FLAG_ENUM.ADS_UF_DONT_EXPIRE_PASSWD;
              de.CommitChanges();
              impersonate.StopImpersonate();
              de.Close();
         }
 
         ///
         ///禁用指定公共名称的用户
         ///
         ///
用户公共名称
         public static void DisableUser(string commonName)
         {
              DisableUser(GetDirectoryEntry(commonName));
         }
 
         ///
         ///禁用指定 的用户
         ///
         ///
         public static void DisableUser(DirectoryEntry de)
         {
              impersonate.BeginImpersonate();
              de.Properties["userAccountControl"][0]=ADHelper.ADS_USER_FLAG_ENUM.ADS_UF_NORMAL_ACCOUNT | ADHelper.ADS_USER_FLAG_ENUM.ADS_UF_DONT_EXPIRE_PASSWD | ADHelper.ADS_USER_FLAG_ENUM.ADS_UF_ACCOUNTDISABLE;
              de.CommitChanges();
              impersonate.StopImpersonate();
              de.Close();
         }
 
         ///
         ///将指定的用户添加到指定的组中。默认为 Users 下的组和用户。
         ///
         ///
用户公共名称
         ///
组名
         public static void AddUserToGroup(string userCommonName, string groupName)
          {
              DirectoryEntry oGroup = GetDirectoryEntryOfGroup(groupName);
              DirectoryEntry oUser = GetDirectoryEntry(userCommonName);
             
              impersonate.BeginImpersonate();
              oGroup.Properties["member"].Add(oUser.Properties["distinguishedName"].Value);
              oGroup.CommitChanges();
              impersonate.StopImpersonate();
 
              oGroup.Close();
              oUser.Close();
         }
 
         ///
         ///将用户从指定组中移除。默认为 Users 下的组和用户。
         ///
         ///
用户公共名称
         ///
组名
         public static void RemoveUserFromGroup(string userCommonName, string groupName)
         {
              DirectoryEntry oGroup = GetDirectoryEntryOfGroup(groupName);
              DirectoryEntry oUser = GetDirectoryEntry(userCommonName);
             
              impersonate.BeginImpersonate();
              oGroup.Properties["member"].Remove(oUser.Properties["distinguishedName"].Value);
              oGroup.CommitChanges();
              impersonate.StopImpersonate();
 
              oGroup.Close();
              oUser.Close();
         }
 
     }
 
     ///
     ///用户模拟角色类。实现在程序段内进行用户角色模拟。
     ///
     public class IdentityImpersonation
     {
         [DllImport("advapi32.dll", SetLastError=true)]
         public static extern bool LogonUser(String lpszUsername, String lpszDomain, String lpszPassword, int dwLogonType, int dwLogonProvider, ref IntPtr phToken);
 
         [DllImport("advapi32.dll", CharSet=CharSet.Auto, SetLastError=true)]
         public extern static bool DuplicateToken(IntPtr ExistingTokenHandle, int SECURITY_IMPERSONATION_LEVEL, ref IntPtr DuplicateTokenHandle);
 
         [DllImport("kernel32.dll", CharSet=CharSet.Auto)]
         public extern static bool CloseHandle(IntPtr handle);
 
         // 要模拟的用户的用户名、密码、域(机器名)
         private String _sImperUsername;
         private String _sImperPassword;
         private String _sImperDomain;
         // 记录模拟上下文
         private WindowsImpersonationContext _imperContext;
         private IntPtr _adminToken;
         private IntPtr _dupeToken;
         // 是否已停止模拟
         private Boolean _bClosed;
 
         ///
         ///构造函数
         ///
         ///
所要模拟的用户的用户名
         ///
所要模拟的用户的密码
         ///
所要模拟的用户所在的域
         public IdentityImpersonation(String impersonationUsername, String impersonationPassword, String impersonationDomain)
         {
              _sImperUsername = impersonationUsername;
              _sImperPassword = impersonationPassword;
              _sImperDomain = impersonationDomain;
 
              _adminToken = IntPtr.Zero;
              _dupeToken = IntPtr.Zero;
              _bClosed = true;
         }
 
         ///
         ///析构函数
         ///
         ~IdentityImpersonation()
         {
              if(!_bClosed)
              {
                   StopImpersonate();
              }
         }
 
         ///
         ///开始身份角色模拟。
         ///
         ///
         public Boolean BeginImpersonate()
         {
              Boolean bLogined = LogonUser(_sImperUsername, _sImperDomain, _sImperPassword, 2, 0, ref _adminToken);
                       
              if(!bLogined)
              {
                   return false;
              }
 
              Boolean bDuped = DuplicateToken(_adminToken, 2, ref _dupeToken);
 
              if(!bDuped)
              {
                   return false;
              }
 
              WindowsIdentity fakeId = new WindowsIdentity(_dupeToken);
              _imperContext = fakeId.Impersonate();
 
              _bClosed = false;
 
              return true;
         }
 
         ///
         ///停止身分角色模拟。
         ///
         public void StopImpersonate()
         {
              _imperContext.Undo();
              CloseHandle(_dupeToken);
              CloseHandle(_adminToken);
              _bClosed = true;
         }
     }
 
}
=====================================================
简单的应用
[WebMethod]
  public string IsAuthenticated(string UserID,string Password)
  {
            string _path = "LDAP://" + adm + "/DC=lamda,DC=com,DC=cn";//"LDAP://172.75.200.1/DC=名字,DC=com,DC=cn";
   string _filterAttribute=null;
  
   DirectoryEntry entry = new DirectoryEntry(_path,UserID,Password);
   
   try
   {
    //Bind to the native AdsObject to force authentication.
    DirectorySearcher search = new DirectorySearcher(entry);
    search.Filter = "(SAMAccountName=" + UserID + ")";
    SearchResult result = search.FindOne();
    
    if(null == result)
    {
     _filterAttribute="登录失败: 未知的用户名或错误密码.";
    }
    else
    {
     _filterAttribute="true";
    }
   
   }
   catch (Exception ex)
   {
//    if(ex.Message.StartsWith("该服务器不可操作")) 
//    {
//     string mail = ADO.GetConnString("mail");
//     entry.Path = "LDAP://"+mail+"/OU=名字,DC=it2004,DC=gree,DC=com,DC=cn";
//     try
//     { 
//      DirectorySearcher search = new DirectorySearcher(entry);
//      search.Filter = "(SAMAccountName=" + UserID + ")";
//      SearchResult result = search.FindOne();
//
//      if(null == result)
//      {
//       _filterAttribute="登录失败: 未知的用户名或错误密码.";
//      }
//      else
//      {
//       _filterAttribute="true";
//      }
//      return _filterAttribute;
//   
//     }
//     catch (Exception ex1)
//     {
//      return ex1.Message;
//     }
//     
//    }
//    else
     return ex.Message;
   }
   return _filterAttribute;
  }
  [WebMethod]
  public string[] LDAPMessage(string UserID)
  {
   string _path = "LDAP://"+adm+"/DC=it2004,DC=名字,DC=com,DC=cn";
   string[] _filterAttribute=new string[5];
   string[] msg = {"samaccountname","displayname","department","company"};
DirectoryEntry entry = new DirectoryEntry(_path,"180037","790813");
try
   {
Object obj = entry.NativeObject;
    
    DirectorySearcher search = new DirectorySearcher(entry);
    search.Filter = "(SAMAccountName=" + UserID + ")";
    SearchResult result = search.FindOne();
if(null == result)
    {
     _filterAttribute[0]="登录失败: 未知的用户名或错误密码.";
    }
    else
    {
     _filterAttribute[0]="true";  
     for(int propertyCounter = 1; propertyCounter < 5; propertyCounter++)
     {
       
      if(propertyCounter==4 &&  result.Properties[msg[propertyCounter-1]][0]==null)
       break;
      _filterAttribute[propertyCounter]=result.Properties[msg[propertyCounter-1]][0].ToString();
      
     }
    }
   
   }
   catch (Exception ex)
   {
    //_filterAttribute[0]=ex.Message;
   }
   return _filterAttribute;
  }
  [WebMethod]
  public string[] AllMembers() 
  {
   
   string[] msg;
   string _path = "LDAP://名字";
DirectoryEntry entry = new DirectoryEntry(_path,"180037","790813");
   
 
   //Bind to the native AdsObject to force authentication.
   Object obj = entry.NativeObject;
System.DirectoryServices.DirectorySearcher mySearcher = new System.DirectoryServices.DirectorySearcher(entry);
   mySearcher.Filter = "(SAMAccountName=180037)";
   msg=new string[mySearcher.FindAll().Count];
   int i=0;
   foreach(System.DirectoryServices.SearchResult result in mySearcher.FindAll()) 
   {
    msg[i++]=result.Path;
   }
   return msg;
  }
 
 }