Dim zhanghao As String = "zhouwei"
Dim mima As String = "mima"
If TextBox1.Text = zhanghao And TextBox2.Text = mima Then
MessageBox.Show("登录成功")
主界面.Show()
Else
MessageBox.Show("帐号或密码错误")
End If
现在帐号密码在sql数据库 代码要怎么改

明天给你找代码

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
txtUserName.Text = txtUserName.Text.Trim()
txtPassWord.Text = txtPassWord.Text.Trim()
If (txtUserName.Text = "" Or txtPassWord.Text = "") Then
MessageBox.Show("输入的信息不完整！")
Exit Sub
End If
Dim con As OleDbConnection
con = New OleDbConnection(CnStr)
con.Open()
Dim sqlstr As String
sqlstr = String.Format("select * from users where username='{0}' and password='{1}'", txtUserName.Text, txtPassWord.Text)
Dim cmd As OleDbCommand
cmd = New OleDbCommand(sqlstr, con)
Dim dr As OleDbDataReader
dr = cmd.ExecuteReader()
If (dr.Read) Then
MessageBox.Show("登录成功")
Me.Hide()
Else
MessageBox.Show("登录失败")
End If
End Sub

呃！仔细研究一下