学生用户管理系统(一)

这个东西搞了我两天呀，强大的度娘下加上qq群上大神的指点，终于弄懂了一些皮毛的东西，感觉关于数据库的连接有很多的知识点，等以后学到.net再归纳。

先上代码。

form1:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Data.SqlClient;

namespace WindowsFormsApp2
{
    public partial class Form1 : Form
    {
        int count;
        int time = 150;
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            //string sqlstring = "server=ZJX-PC;database=zjx;Trusted_Connection=SSPI";
            try
            {
                string sqlstring = "server=ZJX-PC;uid=sa;pwd=zjx28963436;database=zjx";
         
                SqlConnection conn = new SqlConnection(sqlstring);
               // SqlConnection comm = new SqlConnection(sqlstring);
                string sql = "Select * from info where id='" + this.textBox1.Text.Trim() + "' and sw='" + this.textBox2.Text.Trim() + "'";
                SqlCommand cmd = new SqlCommand(sql, conn);
               
                
               try
                {
                conn.Open();
                MessageBox.Show("成功");
                 }
                catch (Exception)
                {
                conn.Close();
                MessageBox.Show("密码或用户名不对");
                }

            SqlDataReader dateReader = cmd.ExecuteReader();
                                    
            if (dateReader.Read())
            {
                MessageBox.Show("即将进入画面");
                    timer1.Start();
                    conn.Dispose();
                    conn.Close();
            }
            }
            catch (Exception)
            {
                MessageBox.Show("系统出错！");
               
            }
           
          
        }

        private void button2_Click(object sender, EventArgs e)
        {
            Form2 aa = new Form2();
             aa.Show();
        }

        private void timer1_Tick(object sender, EventArgs e)
        {
            count++;
            progressBar1.Minimum = 0;
            progressBar1.Maximum = time;
            progressBar1.Visible = true;
            progressBar1.Value = count;
            Application.DoEvents();
            if (count == time)
            {
                timer1.Stop();
                MessageBox.Show("欢迎");
                Form3 xx = new Form3();
                xx.Show();
                this.Hide();
                count = 0;
                progressBar1.Value = count;
                progressBar1.Visible = false;
            }
        }
    }
}

Form2:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Data.SqlClient;


namespace WindowsFormsApp2
{
    public partial class Form2 : Form
    {
        string bb;
        bool aa;
        public Form2()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            
            string sqlstring = "server=ZJX-PC;uid=sa;pwd=zjx28963436;database=zjx";
            SqlConnection conn = new SqlConnection(sqlstring);
            if (textBox1.Text != "" && textBox2.Text != "")
            {
                conn.Open();
                string sql = " insert into info(id,sw) values ('" + textBox1.Text + "'," + "'" + textBox2.Text + "') "; //要执行的 sql 语句
                string sql2 ="Select id from info where id ='" + this.textBox1.Text.Trim() + "'";
                SqlCommand cmd = new SqlCommand(sql, conn);//同登录
                SqlCommand cmd2 = new SqlCommand(sql2, conn);
                cmd.CommandText = sql;
                try
                {
                  bb = cmd2.ExecuteScalar().ToString();
                    MessageBox.Show("用户已存在！");
                    textBox1.Clear();
                    textBox2.Clear();
                    //aa = false;
                }
                catch (Exception)
                {

                   // MessageBox.Show("用户没用过");
                   // aa = true;
                    int i = int.Parse(cmd.ExecuteNonQuery().ToString());
                    if (i > 0)
                    {
                        MessageBox.Show("恭喜你注册成功！", "!");
                        this.Close();
                    }
                }
            }
            else
            {
                MessageBox.Show("不能为空", "警告");
                textBox1.Clear();
                textBox2.Clear();
            }
            conn.Close();
         }  
               
            }
  }
    

Form3:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace WindowsFormsApp2
{
    public partial class Form3 : Form
    {
        public Form3()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            Application.Exit();
        }
    }
}