C#通过XElement从XML文件中读取与值相关的内容

我必须读出C#中所有与用户名相关的设置（参数："name"answers"visible"），并将其按"name"然后"visible'"的顺序存储到列表中，依此类推

因此列表内容应为（客户端用户名："Service"）：

Name-of-Service-Setting-1
True1S
Name-of-Service-Setting-2
True2S
Name-of-Service-Setting-3
True3S

但我只得到第一个孩子（在客户端用户名："服务"）：

Name-of-Service-Setting-1
True1S

这是我的C#代码：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Xml;
using System.Xml.Linq;
using System.Reflection;
namespace LinqToXML_Example
{
    public class Program
    {
        public static bool IsUsernameExisting(string username, XElement clients)
        {
            var userName = from p in clients.Elements()
                           where p.Element("Username").Value == username
                           select p.Element("Username").Value;
            foreach (var p in userName)
            {
                return true;
            }
            return false;
        }

        public static List<string> ReadUserSettings(string username, XElement clients)
        {
            List<string> settingsList = new List<string>();

            if (IsUsernameExisting(username, clients))
            {
                var setting = from s in clients.Elements()
                              where s.Element("Username").Value == username
                              select s.Element("Settings");
                foreach (var p in setting)
                {
                    settingsList.Add(p.Element("Setting").Element("Name").Value);
                    settingsList.Add(p.Element("Setting").Element("Visible").Value);
                }
                return settingsList;
            }

            var errorMsg = "Cannot get the username's settings, because of a wrong Username!";
            settingsList.Add(errorMsg);
            return settingsList;
        }


        public static void Query(string username, XElement clients)
        {
            // Readout the Settings of Client:
            Console.WriteLine("Readout all the settings of client " + "'" + username + "':");
            List<string> resultList1 = new List<string>();
            resultList1 = ReadUserSettings(username, clients);
            if (resultList1.Count != 1)
            {
                for (int i = 0; i < resultList1.Count(); i++)
                {
                    Console.WriteLine(resultList1.ElementAt(i));
                }
            }
            else Console.WriteLine(resultList1.ElementAt(0));

            Console.WriteLine("'n- - - - - End-Of-File- - - - - ");
            Console.Read();
        }


        static void Main()
        {
            var asm = Assembly.GetExecutingAssembly();
            var textStream = asm.GetManifestResourceStream("LinqToXML_Example.AccessData.xml");
            var xmlReader = new XmlTextReader(textStream);
            XElement clients = XElement.Load(xmlReader);

            Query("Service", clients);
        }
    }
}

这是我的AccessData.xml文件：

<Client>
  <Username>Administrator</Username>
  <Password>Admin-Password</Password>
  <Settings>
    <Setting>
      <Name>Name-of-Admin-Setting-1</Name>
      <Visible>True1A</Visible>
    </Setting>
    <Setting>
      <Name>Name-of-Admin-Setting-2</Name>
      <Visible>True2A</Visible>
    </Setting>
    <Setting>
      <Name>Name-of-Admin-Setting-3</Name>
      <Visible>True3A</Visible>
    </Setting>
  </Settings>
</Client>

<Client>
  <Username>Service</Username>
  <Password>Service-Password</Password>
  <Settings>
    <Setting>
      <Name>Name-of-Service-Setting-1</Name>
      <Visible>True1S</Visible>
    </Setting>
    <Setting>
      <Name>Name-of-Service-Setting-2</Name>
      <Visible>True2S</Visible>
    </Setting>
    <Setting>
      <Name>Name-of-Service-Setting-3</Name>
      <Visible>True3S</Visible>
    </Setting>
  </Settings>
</Client>

<Client>
  <Username>Customer</Username>
  <Password>Customer-Password</Password>
  <Settings>
    <Setting>
      <Name>Name-of-Customer-Setting-1</Name>
      <Visible>True1C</Visible>
    </Setting>
    <Setting>
      <Name>Name-of-Customer-Setting-2</Name>
      <Visible>True2C</Visible>
    </Setting>
    <Setting>
      <Name>Name-of-Customer-Setting-3</Name>
      <Visible>True3C</Visible>
    </Setting>
  </Settings>
</Client>

foreach (var p in setting)
{
     settingsList.Add(p.Element("Setting").Element("Name").Value);
     settingsList.Add(p.Element("Setting").Element("Visible").Value);
}

foreach (var p in setting.Elements("Setting"))
{
     settingsList.Add(p.Element("Name").Value);
     settingsList.Add(p.Element("Visible").Value);
}