用adodc

Private Sub cmdOK_Click()
On Error GoTo errh:
    Dim rs As ADODB.Recordset
    Set rs = New ADODB.Recordset
    Set rs = cn.Execute("SELECT UserName , Password  FROM 超级用户 ")
    If rs.EOF Then
        rs.Close
        Set rs = Nothing
        Unload Me
        Load FrmMain
        Exit Sub
    End If
    rs.MoveFirst
    Dim i As Integer
    '校验是否为超级用户
    Do
        If rs.Fields("UserName") = txtUserName.Text Then
            If rs.Fields("Password") = txtPassword.Text Then
                UserType = True
                LoginSucceeded = True
                rs.Close
                If txtPassword.Text = "Admin" Then IsAdmin = True
                Unload Me
                Load FrmMain
                Exit Sub
                Exit Do
            End If
        End If
        rs.MoveNext
    Loop Until rs.EOF
    '校验是否为普通用户
    Set rs = cn.Execute("SELECT 学号 FROM 学生 WHERE 学号 =" & "'" & txtPassword.Text & "'")
    If rs.EOF Then
        MsgBox "无效密码或用户名请重试!", , "Login"
        txtPassword.SetFocus
        SendKeys "{Home}+{End}"
    Else
        rs.Close
        UserType = False
        LoginSucceeded = True
        Unload Me
        Load FrmMain
    End If
    Exit Sub
errh:
    MsgBox Err.Description
End Sub

这里面cn.execute是什么,怎么没有定义

Option Explicit
Public UserType As Boolean '如果是true那么是超级用户
Public cn As ADODB.Connection '公共连接对象
Public searchSQL As String
Public IsAdmin As Boolean '判断是否为系统管理员登陆

Public Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long
Public Declare Function ShellExecute Lib "shell32.dll" Alias "ShellExecuteA" (ByVal hwnd As Long, ByVal lpOperation As String, ByVal lpFile As String, ByVal lpParameters As String, ByVal lpDirectory As String, ByVal nShowCmd As Long) As Long

又是API函数,看不懂啊...

楼主相当有才!!!

API不用看懂，会用就可以了......
API不就是函数吗？你看他的参数和返回值就可以了，不过在这个程序中，没看出来API的作用。

有必要用外部函數不?????
Dim strUserid, password As String
Dim objrs As New Recordset
Public objcn As New Connection
Private Sub Form_Load()
 objcn.Open "Provider=SQLOLEDB.1;Persist Security Info=False;User ID=登入名;Initial Catalog=數據庫名;Data Source=計算機名"
    objrs.Open "t_login", objcn, adOpenKeyset, adLockOptimistic
End Sub

Private Sub connamd_Click()
    Form5.Show
    Unload Me
End Sub

Private Sub command_Click()
     strUserid = Text1.Text
    objrs.Requery
    objrs.Find ("id = '" & strUserid & "'")
    If objrs.EOF = False Then
        If IIf(IsNull(objrs.Fields("password")), "", objrs.Fields("password")) = Text2.Text Then
            strid = IIf(IsNull(objrs.Fields("id")), "", objrs.Fields("id"))
            strname = IIf(IsNull(objrs.Fields("name")), "", objrs.Fields("name"))
            Form1.Show
            Unload Me
        Else
            MsgBox "密碼不正確"
            Text2.Text = ""
            Text2.SetFocus
            Exit Sub
        End If
    Else
        MsgBox "帳號不正確"
        Text1.Text = ""
        Text1.SetFocus
        Exit Sub
    End If
End Sub

Private Sub command_Click()
    Unload Me
End Sub