我正在尝试制作一个使用VB.NET连接到MySQL数据库的非常简单的程序。我的程序只有一个窗体和一个标签。我设置了MySQL数据库，使其具有一个表和一个字段（VARCHAR）
名为"Tab1"。我使用PHPMyAdmin手动将值"CLOSED"插入Tab1字段。我希望我的程序将该字段的值更改为OPEN/CLOSED，并且我还希望窗体上的标签文本
点击时也会改变。
So far, I've added the MySQL.data reference to my project and added:

Imports System
Imports System.Data
Imports MySql.Data.MySqlClient

致将军--宣言
我还声明了一个包含MySQL Connection的全局变量：

Public Class Form1

    Dim conn As New MySqlConnection

下面是连接到MySQL的函数：

Private Function Connect(ByVal server As String, ByRef user As String, ByRef password As String, ByRef database As String)
        ' Connection string with MySQL Info
        conn.ConnectionString = "server=" + server + ";" _
        & "user id=" + user + ";" _
        & "password=" + password + ";" _
        & "database=" + database + ";"
        Try
            conn.Open()
            Return True
        Catch ex As MySqlException
            Return MsgBox(ex.Message)
        End Try
    End Function

我让程序在Form_Load上连接到MySQL，如下所示：

Connect("db4free.net", "boomun", "*******", "boomdb")

它连接得很好，但这里有个问题......我想在单击Label1时将字段从CLOSED更改为OPEN。它确实更改了，但在第二次单击时没有更改回来。不知何故，我需要一个工作代码来更新表中的Tab1字段。
以下是我目前掌握的情况：

Private Sub Label1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Label1.Click
        Dim myCommand As New MySqlCommand
        Dim myAdapter As New MySqlDataAdapter
        Dim myData As MySqlDataReader
        Dim SQL As String

        SQL = "SELECT * FROM `boomtable` WHERE `Tab1` = 'CLOSED'"

        myCommand.Connection = conn
        myCommand.CommandText = SQL
        myAdapter.SelectCommand = myCommand
        Try
            myData = myCommand.ExecuteReader()
            myData.Read()
            If myData.HasRows = 0 Then
                ' *** UPDATE boomtable SET Tab1 = CLOSED WHERE Tab1 = OPEN  ***
                Label1.Text = "CLOSED"
                myData.Close()
            Else
                Label1.Text = "OPEN"
                ' *** UPDATE boomtable SET Tab1 = OPEN WHERE Tab1 = CLOSED ***
                myData.Close()
            End If
        Catch ex As MySqlException
            MsgBox(ex.Message)
        End Try

    End Sub

那更新行是不是为我工作...可以请任何人提供一个工作代码？谢谢我真的很感激!!
下面是该项目的全部代码：

Imports System
Imports System.Data
Imports MySql.Data.MySqlClient

Public Class Form1

    Dim conn As New MySqlConnection

    Private Function Connect(ByVal server As String, ByRef user As String, ByRef password As String, ByRef database As String)
        ' Connection string with MySQL Info
        conn.ConnectionString = "server=" + server + ";" _
        & "user id=" + user + ";" _
        & "password=" + password + ";" _
        & "database=" + database + ";"
        Try
            conn.Open()
            Return True
        Catch ex As MySqlException
            Return MsgBox(ex.Message)
        End Try
    End Function

    Private Sub Label1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Label1.Click
        Dim myCommand As New MySqlCommand
        Dim myAdapter As New MySqlDataAdapter
        Dim myData As MySqlDataReader
        Dim SQL As String

        SQL = "SELECT * FROM `boomtable` WHERE `Tab1` = 'CLOSED'"

        myCommand.Connection = conn
        myCommand.CommandText = SQL
        myAdapter.SelectCommand = myCommand
        Try
            myData = myCommand.ExecuteReader()
            myData.Read()
            If myData.HasRows = 0 Then
                ' *** UPDATE boomtable SET Tab1 = CLOSED WHERE Tab1 = OPEN  ***
                Label1.Text = "CLOSED"
                myData.Close()
            Else
                Label1.Text = "OPEN"
                ' *** UPDATE boomtable SET Tab1 = OPEN WHERE Tab1 = CLOSED ***
                myData.Close()
            End If
        Catch ex As MySqlException
            MsgBox(ex.Message)
        End Try

    End Sub

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Connect("db4free.net", "boomun", "boom123", "boomdb")
    End Sub

End Class