C＃Principal System.DirectoryServices.AccountManagement EmailAddress

Question

我觉得我在这里失去了理智。我正在用一个人的姓名查询AD以获取他们的AD ID和电子邮件地址。在设计时，没有EmailAddress属性，但在运行时它存在。如果在设计时对其进行编码，如果无法编译，那么我在运行时如何访问此EmailAddress？

private Dictionary<string, string> GetActiveDirectoryID(string firstName, string lastName)
        {
            var result = new Dictionary<string, string>();

            PrincipalContext ctx = new PrincipalContext(ContextType.Domain);

            // query AD by first and last name
            UserPrincipal qbeUser = new UserPrincipal(ctx);
            qbeUser.GivenName = firstName;
            qbeUser.Surname = lastName;

            PrincipalSearcher srch = new PrincipalSearcher(qbeUser);

            var found = srch.FindOne();

            result.Add("id", found.SamAccountName);
            result.Add("email", found.EmailAddress);    //??

            return result;
        }