C#2010做的数据库跪求两个so easy的问题
using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows.Forms;

namespace 航空机票预订管理系统
{
    static class Program
    {
        public static int exit = 0;
        /// <summary>
        /// 应用程序的主入口点。
        /// </summary>
        [STAThread]
        static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new login());
            Application.Run(new Staff());
            if (login.canlog == true && login.UType == 0)
            {
                exit = 0;
                for (; ; )
                {
                    Application.Run(new Management());
                    switch (Management.choice)
                    {
                        case button1: Application.Run(new booking()); break;
                        case button2: Application.Run(new passenger()); break;
                        case button3: Application.Run(new Flight()); break;
                        case button4: Application.Run(new ticket()); break;
                        case button5: Application.Run(new refund()); break;
                        case button6: Application.Run(new Staff()); break;
                    }
                }
         &n