程序代码：

Private Sub CmdLogin_Click()
Static n As Integer
If n >= 3 Then
    MsgBox "输入用户名或密码次数大于3次，不允许继续登陆"
    End
End If
Set conn = New ADODB.Connection
Call SJK(conn)
Dim sql As String
Dim rs_login As New ADODB.Recordset
        If Trim(TextName.Text) = "" Then
        MsgBox "用户名不能为空，请重新输入！", vbOKOnly + vbExclamation, "错误"
        TextName.SetFocus
     Else
        sql = "select 员工号,密码,姓名,权限 from 管理组 where 员工号='" & Trim(TextName.Text) & " ' and 密码= '" & Trim(TextPsw.Text) & " 'and 姓名= '" & name & " ' and 权限= '" & Class & " '"   
        rs_login.Open sql, conn, adOpenKeyset, adLockPessimistic
        uname = name    
        Pclass = Class   
     If rs_login.EOF = True Then
        MsgBox "用户名或密码不存在，请重新输入！", vbOKOnly + vbExclamation, "错误"
        TextName = ""
        TextName.SetFocus
     Else '检测密码正确与否
     If Trim(rs_login.Fields("密码")) = Trim(TextPsw) Then
        rs_login.Close
        Unload Me
        FormHome.Show
     Else
        n = n + 1
        MsgBox "第" & n & "次用户名或密码错误，请重新输入！", vbOKOnly + vbExclamation, "错误"
        TextPsw.SetFocus
      End If
     End If
    End If
End Sub

程序代码：

Public conn As New ADODB.Connection, rs As New ADODB.Recordset
Public uname As String, Pclass As String


Public Sub SJK(conn)
   conn.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source= C:\Users\鹏\Desktop\管理系统\Database1.mdb;Persist Security Info=False"
   conn.Open
End Sub