第3章 数据库操作-通过DataGridView控件进行数据库的操作

通过DataGridView控件进行数据库的操作

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.OleDb;
using System.IO;
using System.Security.Cryptography;

namespace WindowsFormsApp1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        private string sql = "select * from 表1";
        private string connectionName = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source="+  Directory.GetCurrentDirectory()+ "\\Database.mdb;";
        private void button1_Click(object sender, EventArgs e)
        {
            OleDbConnection conn = new OleDbConnection(connectionName);
            conn.Open();
            OleDbCommand cmd = new OleDbCommand(sql,conn);
            OleDbDataAdapter apt = new OleDbDataAdapter(cmd);
            DataTable table = new DataTable();
            apt.Fill(table);


            dataGridView1.DataSource = table;

            apt.Dispose();


            //查询数据到textBox1
            string sql2 = "select 体重 from 表1";
        cmd=new OleDbCommand(sql2, conn);
            OleDbDataReader oleDbDataReader = cmd.ExecuteReader();

            //每次读一行数据
            oleDbDataReader.Read();
            oleDbDataReader.Read();
            textBox1.Text = oleDbDataReader[0].ToString();
            oleDbDataReader.Close();
            conn.Close();

            //update数据
            string sql3 = "update 表1 set 姓名='王五' where 年龄=20";
            OleDbConnection conn2 = new OleDbConnection(connectionName);
            conn2.Open();
            cmd = new OleDbCommand(sql3, conn2);
            cmd.ExecuteNonQuery();
            conn.Close();
    }
    }
}