①先下载安装mysql-connector-net，然后在“项目”–“添加引用”–添加“MySQL.Data.dll”
②在MySQL中建立一个数据库test，建立一个表 user，字段包括：id，name，pwd。
代码如下：

Imports MySql.Data.MySqlClient ’引入MySQL

Public Class Form1
Dim connStr As String = "server=localhost; uid=root; pwd=123; database=test"  ' 定义公共的MySQL数据库链接字符串
Dim conn As New MySqlConnection(connStr)    '实例化MySQL连接

Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
    Dim sql As String = "select * from user"  ' 写sql 语句
    DataGridView2.DataSource = SelectDB(sql) '将Data Table中的数据传给DataGridView1的datasource显示
End Sub

Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
    Dim sql As String = "update user set name=120 where id=1 "  ' 写sql 语句
    If UpdateDel(sql) = 1 Then
        MsgBox("执行成功")
        Button2_Click(sender, e)’在调用显示数据，刷新一下
    Else
        MsgBox("执行失败")
    End If
End Sub

Public Function SelectDB(ByVal SQL As String) As DataTable '获取数据库数据函数
    Dim SDA As MySqlDataAdapter ' 声明连接器
   SDA = New MySqlDataAdapter (SQL, conn) ' 实例化连接器
    Dim Dst As New DataSet ’声明并实例化DataSet
    Try
        SDA.Fill(Dst)
        Return Dst.Tables(0)
    Catch ex As Exception
        Return Nothing
    Finally
        conn.Close()
    End Try
End Function

Public Function UpdateDel(ByVal SQL As String) As Integer '添加，更新，删除数据函数
    Dim cmmd As MySqlCommand = New MySqlCommand(SQL, conn) ' 声明并实例化命令器
    Try
        conn.Open()
        Return cmmd.ExecuteNonQuery()
    Catch ex As Exception
        Return 0
    Finally
        conn.Close()
    End Try
End Function
End Class