Option Explicit

'窗口始终在最前

Public Declare Function SetWindowPos Lib "user32" (ByVal hwnd As Long, ByVal hWndInsertAfter As Long, ByVal x As Long, ByVal y As Long, ByVal cx As Long, ByVal cy As Long, ByVal wFlags As Long) As Long
Public Const HWND_TOPMOST& = -1
' 将窗口置于列表顶部，并位于任何最顶部窗口的前面
Public Const SWP_NOSIZE& = &H1
' 保持窗口大小
Public Const SWP_NOMOVE& = &H2

Dim cnn As ADODB.Connection
Dim rs As ADODB.Recordset
Dim strSQL As String

Dim LoginSuccess(0 To 5)

Private Sub Command1_Click(Index As Integer)

    Select Case Index
        Case 0
           
            If Me.DataCombo1.Text = "" Or Text1.Text = "" Then   '当用户名或密码未填时，提示错误
                MsgBox "Login Error!", vbInformation, Me.Caption
                Text1.SetFocus
                Exit Sub
            End If
           
            rs.Close
            '查询出与用户名相同的记录
            strSQL = "SELECT * FROM User_Table WHERE UserID='" & Me.DataCombo1.Text & "'"
            rs.Open strSQL, cnn, adOpenStatic, adLockReadOnly
   
            If Text1.Text = rs.Fields("UserPWD").Value Then    '如果密码与记录相同
                Me.Hide
                Form2.Show
                              
                LoginSuccess(0) = Me.DataCombo1.Text    '用户名
                LoginSuccess(1) = rs.Fields("UserLevel").Value '用户级别
                LoginSuccess(2) = Format(Now, "YYYY-MM-DD HH:MM:SS")    '登录时间
            Else
                MsgBox "Login Error!", vbInformation, Me.Caption
                Text1.Text = ""
                Text1.SetFocus
            End If
        Case 1
            rs.Close
            cnn.Close
            Set cnn = Nothing
            Set FormLogin = Nothing
            End
    End Select
   
End Sub

Private Sub DataCombo1_Change()
    Text1.SetFocus
End Sub

Private Sub Form_Load()

'窗口位于最前，API
    SetWindowPos Me.hwnd, HWND_TOPMOST, 0, 0, 0, 0, SWP_NOMOVE Or SWP_NOSIZE

'引用 Microsoft ActiveX Data Objects 2.8 Library

'连接Access数据库
    Set cnn = New ADODB.Connection
        cnn.Provider = "Microsoft.Jet.OLEDB.4.0"
    Dim cnnFile As String
        cnnFile = "Data Source=" & App.Path & "\data.mdb;Persist Security Info=False;Jet OLEDB:Database Password=123456789"
    cnn.Open cnnFile
'查询用户表，并将用户名显示在DataCombo控件中
    Set rs = New ADODB.Recordset
        strSQL = "SELECT UserID FROM User_Table"
    rs.Open strSQL, cnn, adOpenStatic, adLockReadOnly 'Open table "User"
   
    Set Me.DataCombo1.DataSource = rs
    Set Me.DataCombo1.RowSource = rs
    Me.DataCombo1.ListField = rs.Fields("UserID").Name

End Sub

Private Sub Form_QueryUnload(Cancel As Integer, UnloadMode As Integer)
    rs.Close
    cnn.Close
    Set cnn = Nothing
    Set FormLogin = Nothing
    End
End Sub