C# - 为什么它给每个人 vip？

Question

I am making a project and i thought i had everything working. i am trying to make it to where if the user has vip (or if vip is equal to 1) it will open a new form. the problem though is that when one person has vip then everyone does (or if vip is equal to 1 for one person)

I have tried a lot of things. and nothing has worked so far.

Here is the button code:

private void MaterialFlatButton4_Click(object sender, EventArgs e)
{
    List<User> users = User.GetUsers();
    bool NotVip = true;

    foreach (User u in users)
    {
        ListViewItem item = new ListViewItem(new string[] { u.Id.ToString(), u.Username, u.Password, u.VIP.ToString() });
        item.Tag = u;
        if (u.VIP == 1)
        {
            NotVip = false;

            MessageBox.Show("Nothing in here works yet", "<3", MessageBoxButtons.OK);
            this.Hide();
            Form3 f3 = new Form3();
            f3.ShowDialog();
        }
    }
    if (NotVip == true)
    {
        //Failed to login.
        MessageBox.Show("You do not have vip.\n\nPlease purchase and then try again", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
    }
}

Here is the User.cs code

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using MySql.Data.MySqlClient;

namespace ch
{
    class User
    {
        //database stuff
        private const String SERVER = "localhost";
        private const String DATABASE = "project";
        private const String UID = "root";
        private const String PASSWORD = "********";
        private static MySqlConnection dbConn;

        // User class stuff
        public int Id { get; private set; }

        public String Username { get; private set; }

        public String Password { get; private set; }

        public int VIP { get; private set; }



        private User(int id, String u, String p, int v)
        {
            Id = id;
            Username = u;
            Password = p;
            VIP = v;
        }

        public static void InitializeDB()
        {
            MySqlConnectionStringBuilder builder = new MySqlConnectionStringBuilder();
            builder.Server = SERVER;
            builder.UserID = UID;
            builder.Password = PASSWORD;
            builder.Database = DATABASE;

            string connString = builder.ToString();

            builder = null;

            Console.WriteLine(connString);

            dbConn = new MySqlConnection(connString);

            Application.ApplicationExit += (sender, args) => {
                if (dbConn != null)
                {
                    dbConn.Dispose();
                    dbConn = null;
                }
            };
        }

        public static List<User> GetUsers()
        {
            List<User> users = new List<User>();

            String query = "SELECT * FROM accounts";

            MySqlCommand cmd = new MySqlCommand(query, dbConn);

            dbConn.Open();

            MySqlDataReader reader = cmd.ExecuteReader();

            while (reader.Read())
            {
                int id = (int)reader["id"];
                String username = reader["username"].ToString();
                String password = reader["password"].ToString();
                int v = (int)reader["vip"];


                User u = new User(id, username, password, v);

                users.Add(u);
            }

            reader.Close();

            dbConn.Close();

            return users;
        }
    }
}

I expected a new form to open ONLY IF the logged in user has vip (and not open it for everyone if one user has vip)

Answer 1

The code is doing what you're telling it to do.

In your GetUsers() method you get a list of users. Then you iterate through the items, and if (u.VIP == 1) then you open up a window. Assuming there are multiple records with VIP == 1 , it would of course open a window multiple times.

If you want to do that only when current user has VIP permission, you probably want to look up current user credentials in the acquired user list (assuming that it is found there), and if indeed the user has VIP permissions then open the new window.