login.frm

关于VB数据库的开发问题

VERSION 5.00
Begin VB.Form frmLogin 
   BorderStyle     =   3  'Fixed Dialog
   Caption         =   "请登录"
   ClientHeight    =   2580
   ClientLeft      =   2835
   ClientTop       =   3480
   ClientWidth     =   4245
   LinkTopic       =   "Form1"
   MaxButton       =   0   'False
   MinButton       =   0   'False
   ScaleHeight     =   1524.349
   ScaleMode       =   0  'User
   ScaleWidth      =   3985.824
   ShowInTaskbar   =   0   'False
   StartUpPosition =   2  '屏幕中心
   Begin VB.Frame fraUser 
      Caption         =   "选择身份"
      Height          =   735
      Left            =   120
      TabIndex        =   5
      Top             =   120
      Width           =   3975
      Begin VB.OptionButton optUserType 
         Caption         =   "学生"
         Height          =   375
         Index           =   1
         Left            =   2280
         TabIndex        =   9
         Top             =   240
         Width           =   1095
      End
      Begin VB.OptionButton optUserType 
         Caption         =   "教务管理人员"
         Height          =   375
         Index           =   0
         Left            =   360
         TabIndex        =   8
         Top             =   240
         Width           =   1455
      End
   End
   Begin VB.Frame frmLogin 
      Caption         =   "登录"
      Height          =   1455
      Left            =   120
      TabIndex        =   2
      Top             =   960
      Width           =   3975
      Begin VB.CommandButton cmdCancel 
         Cancel          =   -1  'True
         Caption         =   "取消"
         Height          =   390
         Left            =   2880
         TabIndex        =   7
         Top             =   840
         Width           =   900
      End
      Begin VB.CommandButton cmdOK 
         Caption         =   "确定"
         Default         =   -1  'True
         Height          =   390
         Left            =   2880
         TabIndex        =   6
         Top             =   360
         Width           =   900
      End
      Begin VB.TextBox txtPwd 
         Height          =   345
         IMEMode         =   3  'DISABLE
         Left            =   1080
         PasswordChar    =   "*"
         TabIndex        =   1
         Top             =   885
         Width           =   1485
      End
      Begin VB.TextBox txtUser 
         Height          =   345
         Left            =   1080
         TabIndex        =   0
         Top             =   360
         Width           =   1485
      End
      Begin VB.Label lblLabels 
         AutoSize        =   -1  'True
         Caption         =   "用户名："
         Height          =   195
         Index           =   0
         Left            =   360
         TabIndex        =   4
         Top             =   390
         Width           =   720
      End
      Begin VB.Label lblLabels 
         AutoSize        =   -1  'True
         Caption         =   "口令："
         Height          =   195
         Index           =   1
         Left            =   540
         TabIndex        =   3
         Top             =   915
         Width           =   540
      End
   End
End
Attribute VB_Name = "frmLogin"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Option Explicit

'表示当前用户登录所选择的身份，即用户类型, 0-表示教务管理人员；1-表示学生
Dim mnUserType As Integer

Private Sub cmdCancel_Click()
    Unload Me
End Sub

Private Sub cmdOK_Click()
    '取得用户输入的用户名和密码
    Dim user As String, pwd As String
    user = txtUser
    pwd = txtPwd
        
    '根据不同的身份，选择不同的表用以查询
    Dim r As New ADODB.Recordset
    Set r = DataEnv.rssqlSeek
    Dim strSQL As String
    Select Case mnUserType
        Case 0: '若身份为管理员
            strSQL = "select * from admin where name='" & user & "' and pwd='" & pwd & "'"
        Case 1: '若身份为学生
            strSQL = "select * from student where name='" & user & "' and serial='" & pwd & "'"
    End Select
    
    On Error Resume Next
    '查询DataEnv.rssqlSeek的状态，如果已经打开，则先关闭
    If r.State = adStateOpen Then r.Close
    r.Open strSQL       '根据strSQL的内容刷新DataEnv.rssqlSeek
       
    '用户密码错误的次数，如果错误次数超过3次，则退出系统
    Static nTryCount As Integer
    
    If r.EOF Then   '登录失败
      MsgBox "对不起，无此用户或者密码不正确！请重新输入！！", vbCritical, "错误"
      txtUser.SetFocus
      txtUser.SelStart = 0
      txtUser.SelLength = Len(txtUser)
      nTryCount = nTryCount + 1
      If nTryCount >= 3 Then
         MsgBox "您无权操作本系统!再见！", vbCritical, "无权限"
         Unload Me
      End If
    Else            '登陆成功
      '显示MDI窗体, 并将用户类型和用户名传到MDI窗体中的mnUserType, msUserName中
      Load MDIMain
      With MDIMain
        .mnUserType = mnUserType
        .msUserName = pwd
        .Show
      End With
      Unload Me
    End If
End Sub

Private Sub Form_Load()
    optUserType(0).Value = True
End Sub

Private Sub optUserType_Click(Index As Integer)
    mnUserType = Index
End Sub