要实现教师，管理员，学生登陆··········救救我···我是初学者··

FormLogin.cs//登录窗体
（参考）
C# code
using System;
using System.Collections.Generic;
using
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace SnKsxs//你的名字,呵呵
{
    public partial class FormLogin : Form
    {
        public FormLogin()
        {
            InitializeComponent();
        }

        private void btnLogin_Click(object sender, EventArgs e)
        {
            if (txtUserName.Text=="aaa"&txtPassword.Text=="bbb")//举例的,没有使用数据库
            {
                ValueClass.LoginUserName = txtUserName.Text;
                this.DialogResult = DialogResult.OK;
            }
            else
            {
                MessageBox.Show("用户名或密码错误!", "出错啦~~", MessageBoxButtons.OK, MessageBoxIcon.Information);
                txtPassword.Focus();
                return;
            }
            return;
        }

        private void btnCancel_Click(object sender, EventArgs e)
        {
            Application.ExitThread();
        }
    }
}



FormMain.cs//程序主窗体
C# code
using System;
using System.Collections.Generic;
using
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace SnKsxs
{
    public partial class FormMain : Form
    {
        public FormMain()
        {
            InitializeComponent();
        }

        private void FormMain_Load(object sender, EventArgs e)
        {
            label1.Text = ValueClass.LoginUserName;
        }
    }
}



Program.cs
C# code
using System;
using System.Collections.Generic;
using System.Windows.Forms;

namespace SnKsxs
{
    static class Program
    {
        /// <summary>
        /// 应用程序的主入口点。
        /// </summary>
        [STAThread]
        static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            //Application.Run(new FormLogin());
            FormLogin log = new FormLogin();
            if (log.ShowDialog() == DialogResult.OK)
                Application.Run(new FormMain());
        }
    }
}



ValueClass.cs//用于传值
C# code
using System;
using System.Collections.Generic;
using System.Text;

namespace SnKsxs
{
    class ValueClass
    {
        public static string LoginUserName = string.Empty;
    }
}

放一个下拉文本框
在里面选择登陆方式
在根据选择的登陆方式来判断是什么登陆啊

根据输入的用户名，判断数据哭中的权限设置就可以了啊