login.frm

这里上传一个简单的学生资料管理系统

VERSION 5.00
Begin VB.Form login 
   Caption         =   "用户登录"
   ClientHeight    =   3615
   ClientLeft      =   60
   ClientTop       =   345
   ClientWidth     =   5340
   BeginProperty Font 
      Name            =   "宋体"
      Size            =   12
      Charset         =   134
      Weight          =   700
      Underline       =   0   'False
      Italic          =   0   'False
      Strikethrough   =   0   'False
   EndProperty
   Icon            =   "login.frx":0000
   LinkTopic       =   "Form1"
   MDIChild        =   -1  'True
   ScaleHeight     =   3615
   ScaleWidth      =   5340
   WindowState     =   2  'Maximized
   Begin VB.TextBox Text1 
      Height          =   375
      Left            =   1920
      TabIndex        =   0
      Top             =   1320
      Width           =   1695
   End
   Begin VB.TextBox Text2 
      Height          =   375
      IMEMode         =   3  'DISABLE
      Left            =   1920
      MaxLength       =   10
      PasswordChar    =   "*"
      TabIndex        =   1
      Top             =   1800
      Width           =   1695
   End
   Begin VB.Data Data1 
      Caption         =   "Data1"
      Connect         =   "Access"
      DatabaseName    =   "stu.mdb"
      DefaultCursorType=   0  '缺省游标
      DefaultType     =   2  '使用 ODBC
      Exclusive       =   0   'False
      Height          =   375
      Left            =   240
      Options         =   0
      ReadOnly        =   0   'False
      RecordsetType   =   1  'Dynaset
      RecordSource    =   "UserID"
      Top             =   3000
      Visible         =   0   'False
      Width           =   2775
   End
   Begin VB.CommandButton Command1 
      Caption         =   "确  定"
      Height          =   495
      Left            =   3360
      TabIndex        =   2
      Top             =   2880
      Width           =   1095
   End
   Begin VB.Label Label3 
      AutoSize        =   -1  'True
      Caption         =   "口  令"
      Height          =   240
      Left            =   960
      TabIndex        =   5
      Top             =   1920
      Width           =   795
   End
   Begin VB.Label Label2 
      AutoSize        =   -1  'True
      Caption         =   "用户名"
      Height          =   240
      Left            =   960
      TabIndex        =   4
      Top             =   1320
      Width           =   780
   End
   Begin VB.Label Label1 
      AutoSize        =   -1  'True
      Caption         =   "用户登录"
      Height          =   240
      Left            =   2040
      TabIndex        =   3
      Top             =   720
      Width           =   1035
   End
End
Attribute VB_Name = "login"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False

Private Sub Command1_Click()
'===================================================
'判断用户输入的名称和口令是否合法
'首先判断输入的用户名是否存在，如果不存在，给出提示
'如果用户名存在，判断输入口令是否正确，如果错误，给出提示
'如果用户名和口令输入正确，卸载本窗体，
'否则，判断是否用完三次机会，并给出相应提示。
'===================================================

    Dim IsUser As Boolean        '用户是否存在
    Dim Pwd As String
    Dim Uname As String
    Static count As Integer      '记录输入口令次数
    
    Pwd = Trim(Text2.Text)
    Uname = Trim(Text1.Text)
    IsUser = False
    
    '比对用户名称和口令的正确与否
    Do While Not Data1.Recordset.EOF
      If Uname = Data1.Recordset.Fields(0) Then
         
         '当用户名和当前记录名称相同时的处理：
         If Pwd = Data1.Recordset.Fields("password") Then
           
           '如果口令输入正确，卸载本窗体
           Unload Me
           mainfrm.Toolbar1.Buttons(2).Enabled = True
           mainfrm.Toolbar1.Buttons(1).Enabled = False
           Exit Sub
      Else
          '如果口令输入错误，给出提示信息
           If count < 2 Then
             MsgBox "口令错误，请重新输入"
             Text2.Text = ""
             Text2.SetFocus
           End If
           IsUser = True     '标志为合法用户
           Exit Do
         End If
      End If
    
      Data1.Recordset.MoveNext   '移动到下一条记录
    Loop
    
    count = count + 1            '输入口令次数加1
    
    '输入三次口令，且口令错误，退出程序
    If count = 3 Then
          MsgBox "非法用户，不能使用本系统"
      End
    End If
    
    '如果没有此用户，显示提示信息
    If Not IsUser Then
      MsgBox "无此用户，请重新登录"
      Text1.Text = ""
      Text1.SetFocus
    End If
    
    Data1.Recordset.MoveFirst
End Sub

Private Sub Form_Load()
    Dim DBStr As String
    
    DBStr = App.Path
    If Right(App.Path, 1) <> "\" Then DBStr = App.Path & "\"
    DBStr = DBStr & "stu.mdb"
    Data1.DatabaseName = DBStr

    Text1.Text = ""
    Text2.Text = ""
End Sub