C# - Liefert ein Dictionary der letzten Anmeldung eines Users

/// <summary>
/// Liefert ein Dictionary der letzten Anmeldung eines Users.
/// Da das Attribut nicht auf alle DC's repliziert wird, werden alle DC's durchsucht.
/// </summary>
/// <param name="User">Der NT-Account (cn)</param>
/// <example>
///   System.Collections.Generic.Dictionary<string, DateTime> UserLastLogon = GetUserLastLogon(Environment.UserName);
///   foreach (KeyValuePair<string, DateTime> kvp in UserLastLogon)
///   {
///      string ServerName = kvp.Key;
///      DateTime LastLogon = kvp.Value;
///   }
/// </example>
public System.Collections.Generic.Dictionary<string, DateTime> GetUserLastLogon(string User)
{
	DateTime DateLastLogon = DateTime.MinValue;
	string LDAPServerName = "";
	System.Collections.Generic.Dictionary<string, DateTime> LastLogon = new System.Collections.Generic.Dictionary<string, DateTime>();
	System.DirectoryServices.ActiveDirectory.Domain Domain = System.DirectoryServices.ActiveDirectory.Domain.GetComputerDomain();
	foreach (System.DirectoryServices.ActiveDirectory.DomainController Server in Domain.DomainControllers)
	{
		object LastLogonLongTime = GetLDAPValue(User, "lastlogon", "user", "LDAP://" + Server.Name);
		if (LastLogonLongTime != null)
		{
			if (System.DateTime.FromFileTime((long)LastLogonLongTime) > DateLastLogon)
			{
				DateLastLogon = System.DateTime.FromFileTime((long)LastLogonLongTime);
				LDAPServerName = Server.Name;
			}
		}
	}
	if (LDAPServerName == "")
	{
		LastLogon.Add("", DateTime.MaxValue);
		return LastLogon;
	}
	else
	{
		LastLogon.Add(LDAPServerName, DateLastLogon);
		return LastLogon;
	}
}