frmlogin.frm

图书馆管理系统

VERSION 5.00
Begin VB.Form frmLogin 
   BorderStyle     =   3  'Fixed Dialog
   Caption         =   "登录"
   ClientHeight    =   4545
   ClientLeft      =   2835
   ClientTop       =   3480
   ClientWidth     =   7395
   BeginProperty Font 
      Name            =   "宋体"
      Size            =   12
      Charset         =   134
      Weight          =   700
      Underline       =   0   'False
      Italic          =   0   'False
      Strikethrough   =   0   'False
   EndProperty
   LinkTopic       =   "Form1"
   MaxButton       =   0   'False
   MinButton       =   0   'False
   Picture         =   "frmLogin.frx":0000
   ScaleHeight     =   2685.336
   ScaleMode       =   0  'User
   ScaleWidth      =   6943.504
   ShowInTaskbar   =   0   'False
   StartUpPosition =   2  '屏幕中心
   Begin VB.ComboBox cmbType 
      Height          =   360
      ItemData        =   "frmLogin.frx":5E98
      Left            =   3195
      List            =   "frmLogin.frx":5E9A
      Style           =   2  'Dropdown List
      TabIndex        =   6
      Top             =   2160
      Width           =   1935
   End
   Begin VB.TextBox txtUserName 
      BeginProperty Font 
         Name            =   "宋体"
         Size            =   9
         Charset         =   134
         Weight          =   400
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      Height          =   345
      Left            =   3240
      TabIndex        =   1
      Top             =   960
      Width           =   2325
   End
   Begin VB.CommandButton cmdOK 
      Caption         =   "确定"
      Default         =   -1  'True
      BeginProperty Font 
         Name            =   "宋体"
         Size            =   10.5
         Charset         =   134
         Weight          =   700
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      Height          =   375
      Left            =   2280
      Picture         =   "frmLogin.frx":5E9C
      Style           =   1  'Graphical
      TabIndex        =   4
      Top             =   3360
      Width           =   1140
   End
   Begin VB.CommandButton cmdCancel 
      Cancel          =   -1  'True
      Caption         =   "取消"
      BeginProperty Font 
         Name            =   "宋体"
         Size            =   10.5
         Charset         =   134
         Weight          =   700
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      Height          =   390
      Left            =   3960
      Picture         =   "frmLogin.frx":1CC08
      Style           =   1  'Graphical
      TabIndex        =   5
      Top             =   3360
      Width           =   1140
   End
   Begin VB.TextBox txtPassword 
      BeginProperty Font 
         Name            =   "宋体"
         Size            =   9
         Charset         =   134
         Weight          =   400
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      Height          =   345
      IMEMode         =   3  'DISABLE
      Left            =   3210
      PasswordChar    =   "*"
      TabIndex        =   3
      Top             =   1605
      Width           =   2325
   End
   Begin VB.Label Label3 
      AutoSize        =   -1  'True
      BackStyle       =   0  'Transparent
      Caption         =   "身  份："
      Height          =   240
      Left            =   1560
      TabIndex        =   7
      Top             =   2160
      Width           =   1035
   End
   Begin VB.Label lblLabels 
      BackColor       =   &H00C0C000&
      BackStyle       =   0  'Transparent
      Caption         =   "用户名称(&U):"
      BeginProperty Font 
         Name            =   "宋体"
         Size            =   10.5
         Charset         =   134
         Weight          =   700
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      Height          =   495
      Index           =   0
      Left            =   1680
      TabIndex        =   0
      Top             =   960
      Width           =   1440
   End
   Begin VB.Label lblLabels 
      BackColor       =   &H00C0C000&
      BackStyle       =   0  'Transparent
      Caption         =   "密码(&P):"
      BeginProperty Font 
         Name            =   "宋体"
         Size            =   10.5
         Charset         =   134
         Weight          =   700
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      Height          =   495
      Index           =   1
      Left            =   1680
      TabIndex        =   2
      Top             =   1560
      Width           =   1440
   End
End
Attribute VB_Name = "frmLogin"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Const MaxLogTimes As Integer = 3    '定义允许尝试登录的最大次数
Private Sub cmdCancel_Click()
   If MsgBox("你选择了退出系统登录，退出将不能启动管理系统！" & vbCrLf _
              & "是否真的退出？", vbYesNo + vbQuestion, "登录验证") = vbYes Then
        Unload Me               '卸载登录窗体
    End If
End Sub

Private Sub cmdOk_Click()
   Dim objCn As Connection, objRs As Recordset, strSQL$
    If Trim(txtusername) = "" Then              '检验是否输入用户名
        MsgBox "请输入用户名！", vbExclamation, "登录验证"
        txtusername = ""
        txtusername.SetFocus
        Exit Sub
    End If
    If Trim(txtpassword) = "" Then   '检验是否输入登录口令
        MsgBox "请输入登录口令！", vbExclamation, "登录验证"
        txtpassword = ""
        txtpassword.SetFocus
        Exit Sub
    End If
    '静态常量intLogTimes用于保存用户请求验证的次数
    Static intLogTimes As Integer
    intLogTimes = intLogTimes + 1     '保存当前登录次数
    If intLogTimes > MaxLogTimes Then
        '超过允许的登录次数，显示提示信息
        MsgBox "你已经超过允许的登录验证次数！" & vbCr _
               & "应用程序将结束！", vbCritical, "登录验证"
        End         '结束应用程序
    End If
    '输入合法，进一步检验正确性
    '创建与数据库的联接
    Set objCn = New Connection                  '实例化联接对象
    With objCn                                  '建立数据库联接
        .Provider = "SQLOLEDB"
        .ConnectionString = "User ID=sa;PWD=;Data Source=(local);" & _
                            "Initial Catalog=datatushu"
        .Open
    End With
    
    '根据用户身份创建SQL Select命令
    Dim objLog As New Recordset
    Select Case cmbType
        Case "1"
            strSQL = "select 密码 as 密码 from 管理者信息 where 权限=1"
        Case "2"
            strSQL = "select 密码 as 密码 from 管理者信息  where 权限=2"
        Case "3"
            strSQL = "select 密码 as 密码 from 管理者信息 where 权限=3"
    End Select
    '执行查询获得用户登陆密码
    Set objRs = New Recordset
    With objRs
        Set .ActiveConnection = objCn
        .CursorLocation = adUseClient
        .CursorType = adOpenStatic
        .Open strSQL
        If .RecordCount < 1 Then
            MsgBox "用户名输入错误！", vbCritical, "登录验证"
            txtusername.SetFocus
            txtusername.SelStart = 0
            txtusername.SelLength = Len(txtusername)
        Else
            If txtpassword.Text = "" Then
                MsgBox "口令错误，请重新输入！", vbCritical, "登录验证"
                txtpassword.SetFocus
                txtpassword = ""
            Else
                '保存当前用户信息
                CurrentUserName = Trim(txtusername)
                CurrentUserPassword = Trim(txtpassword)
                CurrentUserType = cmbType
                '显示登录成功信息
                MsgBox "欢迎使用图书管理系统！", vbInformation, "登录成功"
                Unload Me               '关闭登录窗体
                zhuye.Show         '显示系统主窗体
            End If
        End If
     End With
    objCn.Close             '关闭数据库连接
    Set objCn = Nothing     '释放数据库连接
    Set objRs = Nothing
End Sub
Private Sub Form_Load()
 '清空用户名和口令文本框
    txtusername = ""
    txtpassword = ""
    '创建身份列表
    cmbType.AddItem "1"
    cmbType.AddItem "2"
    cmbType.AddItem "3"
    cmbType.ListIndex = 0
End Sub