VERSION 5.00
Begin VB.Form frmLogin 
   BorderStyle     =   3  'Fixed Dialog
   Caption         =   "請(qǐng)登錄"
   ClientHeight    =   3990
   ClientLeft      =   45
   ClientTop       =   435
   ClientWidth     =   6555
   Icon            =   "Form1.frx":0000
   LinkTopic       =   "Form1"
   MaxButton       =   0   'False
   MinButton       =   0   'False
   Picture         =   "Form1.frx":29C12
   ScaleHeight     =   3990
   ScaleWidth      =   6555
   ShowInTaskbar   =   0   'False
   StartUpPosition =   2  '屏幕中心
   Begin VB.CommandButton cmdCancel 
      Caption         =   "取消"
      Height          =   495
      Left            =   3840
      TabIndex        =   5
      Top             =   3000
      Width           =   1575
   End
   Begin VB.CommandButton cmdOK 
      Caption         =   "確定"
      Height          =   495
      Left            =   1320
      TabIndex        =   4
      Top             =   3000
      Width           =   1575
   End
   Begin VB.TextBox txtPWD 
      Height          =   300
      IMEMode         =   3  'DISABLE
      Left            =   3480
      PasswordChar    =   "*"
      TabIndex        =   3
      Top             =   2040
      Width           =   2055
   End
   Begin VB.ComboBox cmbUserName 
      Height          =   300
      Left            =   3480
      TabIndex        =   2
      Text            =   "cmbUserName"
      Top             =   1200
      Width           =   2055
   End
   Begin VB.Image Image1 
      Height          =   1080
      Left            =   600
      Picture         =   "Form1.frx":387AD
      Top             =   1200
      Width           =   1080
   End
   Begin VB.Label labPWD 
      BackStyle       =   0  'Transparent
      Caption         =   "密  碼："
      BeginProperty Font 
         Name            =   "宋體"
         Size            =   12
         Charset         =   134
         Weight          =   700
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      Height          =   375
      Left            =   1920
      TabIndex        =   1
      Top             =   2040
      Width           =   1455
   End
   Begin VB.Label labUsername 
      BackStyle       =   0  'Transparent
      Caption         =   "用戶名："
      BeginProperty Font 
         Name            =   "宋體"
         Size            =   12
         Charset         =   134
         Weight          =   700
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      Height          =   255
      Left            =   1920
      TabIndex        =   0
      Top             =   1200
      Width           =   1455
   End
End
Attribute VB_Name = "frmLogin"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Dim conn As New ADODB.Connection
Dim rs As New ADODB.Recordset
Dim connstring As String
Dim num As Integer                ' 用于保存密碼輸入錯(cuò)誤次數(shù)
Private Sub CmdCancel_Click()
    Unload frmLogin      '卸載登錄窗口
End Sub

Private Sub cmdOK_Click()
    If Trim(cmbUserName.Text) = "" Then           '首先要求用戶名不能為空
       MsgBox "用戶名不能為空！", vbOKOnly + vbExclamation, "警告！"
       cmbUserName.SetFocus             '將焦點(diǎn)轉(zhuǎn)移到用戶名組合框中
       Exit Sub
    End If
    connstring = "Provider=SQLOLEDB.1;Password=ecc;Persist Security Info=True;User ID=sa;" _
    & "Initial Catalog=PetrolStation System;Server=(local)"
    If conn.State <> 1 Then              '如果數(shù)據(jù)庫沒有打開則打開數(shù)據(jù)庫
        conn.Open (connstring)
    End If
    Set rs = conn.Execute("select * from PS_Users where 用戶='" & Trim(cmbUserName.Text) & "'")
    ' 在users數(shù)據(jù)表中檢索用戶字段值為用戶輸入的用戶名的記錄，將結(jié)果存放在rs記錄集中
    If rs.EOF Then                '  如果記錄為空則說明不存在此條記錄，也說明用戶名錯(cuò)誤
       MsgBox " 沒有該用戶！" & vbCrLf & " 請(qǐng)重新輸入！", vbOKOnly + vbExclamation, "提示"
       cmbUserName.SetFocus
       Exit Sub
    Else                       '存在此用戶名，檢查密碼
        rs.MoveFirst
       If rs.Fields("密碼").Value = Trim(txtPWD.Text) Then  '密碼正確
          Unload frmLogin           '卸載登錄窗口
          Load frmMain              '加載主窗口
          frmMain.Show              '顯示主窗口
       Else                '密碼錯(cuò)誤
          If num < 2 Then   '輸入錯(cuò)誤次數(shù)不足三次
              num = num + 1    '錯(cuò)誤次數(shù)加1
              MsgBox "口令不對(duì)，請(qǐng)重輸！" & vbCrLf & " 您還有" & Str(3 - num) & "次機(jī)會(huì)！", _
                    vbOKOnly + vbExclamation, "提示"       '提示錯(cuò)誤
              txtPWD.SetFocus
              Exit Sub
          Else                     '輸入錯(cuò)誤打到3次，提示后退出系統(tǒng)
              MsgBox "對(duì)不起，您無權(quán)使用本系統(tǒng)！", vbOKOnly + vbExclamation, "提示"
              Unload frmLogin
              Exit Sub
          End If
       End If
    End If
    conn.Close                       '關(guān)閉數(shù)據(jù)庫連接
End Sub

Private Sub Form_Load()
    connstring = "Provider=SQLOLEDB.1;Password=ecc;Persist Security Info=True;User ID=sa;" _
          & "Initial Catalog=PetrolStation System;Server=(local)"
    
    If conn.State <> 1 Then       '如果數(shù)據(jù)庫未打開，則打開數(shù)據(jù)庫
        conn.Open (connstring)
    End If
    Set rs = conn.Execute("select * from PS_Users")  '執(zhí)行查詢操作，結(jié)果保存在rs記錄集中
    With rs
        .MoveFirst
        Do While Not .EOF               '  逐條讀取用戶名稱，添加到cmbUserName組合框中
            DoEvents
            cmbUserName.AddItem (!用戶)
            .MoveNext
        Loop
    End With
    cmbUserName.ListIndex = 0           '將cmbUserName組合框的默認(rèn)選項(xiàng)設(shè)置為第一條
    conn.Close
End Sub