Const MAX_ENTER = 3

Private Sub Command1_Click()
    Static iEnterCount As Integer
    If LCase(Trim(Text1)) = "admin" And LCase(Trim(Text2)) = "admin" Then
        iEnterCount = 0
        MsgBox "登陆成功！"
    Else
        If iEnterCount >= MAX_ENTER Then
            MsgBox "输入错误次数已达三次或以上，程序自动退出。"
            End
        End If
        MsgBox "用户名或密码错误！"
        iEnterCount = iEnterCount + 1
    End If
End Sub