C#登录XML循环密码错误

using System;
using System.Xml;

class Program
{
    static void Main()
    {
        // 读取XML文件
        XmlDocument xmlDoc = new XmlDocument();
        xmlDoc.Load("data.xml");

        // 获取用户输入
        Console.Write("请输入用户名：");
        string username = Console.ReadLine();
        Console.Write("请输入密码：");
        string password = Console.ReadLine();

        // 验证密码
        XmlNodeList userNodes = xmlDoc.SelectNodes("//user");
        bool isAuthenticated = false;

        foreach (XmlNode userNode in userNodes)
        {
            string storedUsername = userNode.SelectSingleNode("username").InnerText;
            string storedPassword = userNode.SelectSingleNode("password").InnerText;

            if (username == storedUsername && password == storedPassword)
            {
                isAuthenticated = true;
                break;
            }
        }

        // 处理密码错误
        if (!isAuthenticated)
        {
            Console.WriteLine("密码错误！");
            // 其他处理逻辑...
        }
        else
        {
            Console.WriteLine("登录成功！");
            // 其他处理逻辑...
        }

        Console.ReadLine();
    }
}

<users>
  <user>
    <username>user1</username>
    <password>password1</password>
  </user>
  <user>
    <username>user2</username>
    <password>password2</password>
  </user>
  <!-- 其他用户... -->
</users>