使用 Vb.net 和 Mysql 作为数据库登录的代码
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codes for Login using Vb.net and Mysql as database
提问by anayaur30
please help to debug my codes. it is a login form , it cant run because of some errors in codes. please help me.. i dont know how to debug it.
i am a beginner in programming.
请帮助调试我的代码。它是一个登录表单，由于代码中的一些错误而无法运行。请帮助我..我不知道如何调试它。
我是编程的初学者。
Imports MySql.Data.MySqlClient
Public Class Form1
' Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Dim cmd As New MySqlCommand
Dim da As New MySqlDataAdapter
Dim con As MySqlConnection = jokenconn()
End Sub'
Public Function jokenconn() As MySqlConnection
Return New MySqlConnection("server=localhost;user id=root;Database=db_ko;")
End Function
Private Sub cmdlogin_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdlogin.Click
Dim connString As String = "Database=db_ko;Data Source=localhost;User ID=root;"
Dim conn As New MySqlConnection(connString)
Dim cmd As New MySqlCommand
Dim user As String = txtusername.Text
Dim pass As String = txtpass.Text
Dim reader As DataTableReader
conn.Open()
cmd.CommandText = "SELECT * FROM `db_account` WHERE username= '" & txtusername.Text & "' and password= '" & txtpass.Text & "', conn"
cmd.Connection = conn
cmd.Parameters.Add(New MySqlParameter("?UserName", txtusername.Text))
cmd.Parameters.Add(New MySqlParameter("?Password", txtpass.Text))
cmd.Connection = conn
'cmd.EndExecuteReader = reader
If reader.HasRows() Then
MessageBox.Show("Login success!", "Success!", MessageBoxButtons.OK, MessageBoxIcon.Information)
Form2.Show()
Me.Close()
Else
MsgBox("Invalid Login information.!", MessageBoxButtons.OK, MessageBoxIcon.Information)
End If
conn.Close()
End Sub
End Class
sorry for the codes are wrong. thank you advance!!
抱歉代码错误。先谢谢了！！
回答by Codemunkeee
you have commented out this line here. Remove " ' "
您已在此处注释掉这一行。消除 ” ' ”
' Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
and change it to
并将其更改为
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
also, try removing the "`" on db_account on this line
另外，尝试删除此行上 db_account 上的“`”
cmd.CommandText = "SELECT * FROM `db_account` WHERE username= '" & txtusername.Text & "' and password= '" & txtpass.Text & "', conn"
to
到
cmd.CommandText = "SELECT * FROM db_account WHERE username= '" & txtusername.Text & "' and password= '" & txtpass.Text & "', conn"
