login.frm

这是一个非常 好的一个程序进行体会一下学生管理系统

VERSION 5.00
Begin VB.Form Form2 
   BackColor       =   &H00FFC0C0&
   BorderStyle     =   1  'Fixed Single
   Caption         =   "系统登录"
   ClientHeight    =   3510
   ClientLeft      =   3525
   ClientTop       =   2880
   ClientWidth     =   5100
   Icon            =   "login.frx":0000
   LinkTopic       =   "Form2"
   MaxButton       =   0   'False
   MinButton       =   0   'False
   ScaleHeight     =   3510
   ScaleWidth      =   5100
   StartUpPosition =   2  '屏幕中心
   Visible         =   0   'False
   Begin VB.CommandButton cmdCancel 
      BackColor       =   &H00FFC0C0&
      Caption         =   "离    开"
      Height          =   495
      Left            =   3000
      Style           =   1  'Graphical
      TabIndex        =   6
      Top             =   2880
      Width           =   1215
   End
   Begin VB.CommandButton cmdOK 
      BackColor       =   &H00FFC0C0&
      Caption         =   "登    录"
      Height          =   495
      Left            =   600
      Style           =   1  'Graphical
      TabIndex        =   2
      Top             =   2880
      Width           =   1215
   End
   Begin VB.TextBox txtPassword 
      BeginProperty Font 
         Name            =   "宋体"
         Size            =   12
         Charset         =   134
         Weight          =   400
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      Height          =   375
      IMEMode         =   3  'DISABLE
      Left            =   1440
      PasswordChar    =   "*"
      TabIndex        =   1
      Top             =   2040
      Width           =   2535
   End
   Begin VB.TextBox txtUserName 
      BeginProperty Font 
         Name            =   "宋体"
         Size            =   12
         Charset         =   134
         Weight          =   400
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      Height          =   375
      Left            =   1440
      TabIndex        =   0
      Text            =   "admin"
      Top             =   1200
      Width           =   2535
   End
   Begin VB.Label Label3 
      Alignment       =   2  'Center
      BackColor       =   &H00FFC0C0&
      Caption         =   "密  码："
      BeginProperty Font 
         Name            =   "宋体"
         Size            =   12
         Charset         =   134
         Weight          =   400
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      Height          =   375
      Left            =   240
      TabIndex        =   5
      Top             =   2040
      Width           =   975
   End
   Begin VB.Label Label2 
      Alignment       =   2  'Center
      BackColor       =   &H00FFC0C0&
      Caption         =   "用户名："
      BeginProperty Font 
         Name            =   "宋体"
         Size            =   12
         Charset         =   134
         Weight          =   400
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      Height          =   255
      Left            =   240
      TabIndex        =   4
      Top             =   1200
      Width           =   975
   End
   Begin VB.Label Label1 
      Alignment       =   2  'Center
      BackColor       =   &H00FFC0C0&
      Caption         =   "教务管理系统"
      BeginProperty Font 
         Name            =   "华文行楷"
         Size            =   21.75
         Charset         =   134
         Weight          =   400
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      Height          =   495
      Left            =   960
      TabIndex        =   3
      Top             =   360
      Width           =   3135
   End
End
Attribute VB_Name = "Form2"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Attribute VB_Ext_KEY = "RVB_UniqueId" ,"41FF01D903CC"
Attribute VB_Ext_KEY = "RVB_ModelStereotype" ,"Form"
Public OK As Boolean
'记录按“确定”的次数
Dim miCount As Integer

Private Sub cmdCancel_Click()
OK = False
Me.Hide
End Sub

Private Sub cmdOK_Click()
'用来存放SQL语句
Dim txtSQL As String
'用来存放记录集对象
Dim mrc As ADODB.Recordset
'用来存放返回信息
Dim MsgText As String
UserName = ""
'判断输入用户名是否为空
If Trim(txtUserName.Text = "") Then
    MsgBox "没有这个用户，请重新输入用户名！", vbOKOnly + vbExclamation, "警告"
    txtUserName.SetFocus
Else
    '查询指定用户名的记录
    txtSQL = "select * from User_info where User_id = " & "'" & Trim(txtUserName.Text) & "'"
    '执行查询语句
    Set mrc = ExecuteSQL(txtSQL, MsgText)
    If mrc.EOF = True Then
        MsgBox "没有这个用户，请重新输入用户名！", vbOKOnly + vbExclamation, "警告"
        txtUserName.SetFocus
    Else
        '判断密码是否正确
        If Trim(mrc.Fields(1)) = Trim(txtPassword.Text) Then
            OK = True
            mrc.Close
            Me.Hide
            UserName = Trim(txtUserName.Text)
        Else
            MsgBox "输入密码不正确，请重新输入！", vbOKOnly + vbExclamation, "警告"
            txtPassword.SetFocus
            txtPassword.Text = ""
        End If
    End If
End If
'记载输入密码次数
miCount = miCount + 1
If miCount = 3 Then
    Me.Hide
End If
Exit Sub
End Sub


Private Sub Form_Load()
    OK = False
    miCount = 0
End Sub

'在输完密码之后，检测按下的是否是回车
Private Sub txtPassword_KeyDown(KeyCode As Integer, Shift As Integer)
    If KeyCode = 13 Then
        Call cmdOK_Click
    End If
End Sub