C#连接MySQL
一、环境搭配
安装MySQL，引用MySql.Data.DLL文件，这个MySql.Data.DLL文件在你安装Mysql的时候已经下载好给你的了。
把它复制到项目的Debug目录下，然后引用即可。
二、连接使用步骤
声明对象，有连接对象，语句执行对象，结果读取对象，在这我们要先引用一下MysqlClient。
//连接对象
MySqlConnection conn=null;
//语句执行对象
MySqlCommand comm=null;
//语句执行结果数据对象
MySqlDataReader dr = null;连接数据库
conn = new MySqlConnection("Database = stu;Server = localhost;Port = 3306;Password = 123456;UserID = root;charset = utf8mb4");sql语句命令对象
comm = new MySqlCommand("select * from user",conn);执行语句获取数据
dr = comm.ExecuteReader(); /*查询*/
//dr = comm.ExecuteNonQuery(); /*增删改*/
while (dr.Read())
{
tbText.Text += dr.GetString("对应表字段名称") + "----" + dr.GetString("password");
tbText.Text += "\r";
}
dr.Close();
conn.Close();注意使用完，我们要关闭掉连接资源。如果连接失败，可能是版本不对，活动平台要修改成x86的平台。
三、功能代码实现
首先创建一个数据库，随便写入几条数据。
CREATE TABLE `user` (
`username` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci NOT NULL,
`password` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
insert into user values('jack','sss');
insert into user values('123','123');布局 有一个CheckedListBox控件，方便勾选删除。
代码
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 MySql.Data.MySqlClient;
using MySql.Data;
namespace MysqlText
{
public partial class frm_main : Form
{
//连接对象
MySqlConnection conn=null;
//语句执行对象
MySqlCommand comm=null;
//语句执行结果数据对象
MySqlDataReader dr = null;
string strConn = "";
public frm_main()
{
InitializeComponent();
strConn = "Database = stu;Server = localhost;Port = 3306;Password = 123456;UserID = root;charset = utf8mb4";
conn = new MySqlConnection(strConn);
}
///
/// 连接
///
///
///
private void btnConn_Click(object sender, EventArgs e)
{
//判断连接状态
if (conn.State != ConnectionState.Open)
{
conn.Open();
tbText.Text = strConn;
label4.Text = "";
label4.Text = "连接成功";
}
}
///
/// 查询
///
///
///
private void btnSel_Click(object sender, EventArgs e)
{
//判断连接状态
if (!CkeckConn())
{
MessageBox.Show("请连接数据库");
return;
}
comm = new MySqlCommand("select * from user", conn);
tbText.Text = "";
dr = comm.ExecuteReader(); /*查询*/
while (dr.Read())
{
tbText.Text += dr.GetString("username") + "----" + dr.GetString("password");
tbText.Text += "\r\n";
}
dr.Close();
ckLBoxsRefresh();
}
///
/// 添加
///
///
///
private void btnAdd_Click(object sender, EventArgs e)
{
//判断连接状态
if (!CkeckConn())
{
MessageBox.Show("请连接数据库");
return;
}
label4.Text = "";
//先判断用户是否已注册
if (tbUser.Text =="" || tbPW.Text=="")
{
label4.Text = "请完善信息";
return;
}
comm = new MySqlCommand("select * from user where username = '" + tbUser.Text + "'", conn);
dr = comm.ExecuteReader();
if (dr.Read())
{
label4.Text = "已存在用户" + tbUser.Text;
}
else
{
dr.Close();
int num = 0;
comm = new MySqlCommand("insert into user values('" + tbUser.Text + "','" + tbPW.Text + "')", conn);
num = comm.ExecuteNonQuery();
if (num > 0)
{
label4.Text = "已添加用户" + tbUser.Text;
ckLBoxsRefresh();
tbText.Text = "";
}
else
{
label4.Text = "添加失败";
}
}
dr.Close();
}
///
/// 修改
///
///
///
private void btnUp_Click(object sender, EventArgs e)
{
//判断连接状态
if (!CkeckConn())
{
MessageBox.Show("请连接数据库");
return;
}
label4.Text = "";
//先判断用户是否已注册
comm = new MySqlCommand("select * from user where username = '" + tbUpUser.Text + "'", conn);
dr = comm.ExecuteReader();
if (dr.Read())
{
dr.Close();
int num = 0;
comm = new MySqlCommand("update user set password = '" + tbUpPW.Text + "'where username = '" + tbUpUser.Text + "'", conn);
num = comm.ExecuteNonQuery();
if (num > 0)
{
label4.Text = "已修改用户" + tbUpUser.Text + "密码";
tbText.Text = "";
}
else
{
label4.Text = "修改失败";
}
}
else
{
label4.Text = "用户不存在";
}
dr.Close();
}
///
/// 删除
///
///
///
private void btnDel_Click(object sender, EventArgs e)
{
//判断连接状态
if (!CkeckConn())
{
MessageBox.Show("请连接数据库");
return;
}
label4.Text = "";
//查找选中
for (int i = 0; i < ckLBoxs.Items.Count; i++)
{
if (ckLBoxs.GetItemChecked(i))
{
int num = 0;
comm = new MySqlCommand("delete from user where username = '" + ckLBoxs.Items[i].ToString() + "'", conn);
num = comm.ExecuteNonQuery();
if (num > 0)
{
label4.Text += "已删除用户" + ckLBoxs.Items[i].ToString()+"\t";
ckLBoxsRefresh();
tbText.Text = "";
}
else
{
label4.Text = "用户不存在";
}
}
}
}
///
/// 判断连接
///
///
/// 列表更新
///
private void ckLBoxsRefresh()
{
//判断连接状态
if (!CkeckConn())
{
MessageBox.Show("请连接数据库");
return;
}
comm = new MySqlCommand("select * from user", conn);
dr = comm.ExecuteReader();
ckLBoxs.Items.Clear();
int num = 0;
while (dr.Read())
{
ckLBoxs.Items.Add(dr.GetString(0));
num++;
}
label4.Text = "";
label4.Text = "已更新数据" + num.ToString() + "条。";
dr.Close();
}
///
/// 退出
///
///
///
private void btn_Exit_Click(object sender, EventArgs e)
{
this.Close();
}
///
/// 关闭
///
///
///
private void frm_main_FormClosing(object sender, FormClosingEventArgs e)
{
if (conn !=null )
{
if (conn.State != ConnectionState.Closed)
{
conn.Close();
}
}
if (dr !=null)
{
dr.Close();
}
}
}
}
四、效果
连接
查询
添加
修改
删除
C#连接mysql以及CRUD的实现就这样，如有什么问题或者交流可以留言或私信me。