Private Sub cmdOK_Click()

txtUserName.Text = Trim(txtUserName.Text)
If txtUserName.Text = "" Then
   MsgBox " 请输入用户名！"
   Exit Sub
End If

txtPassword.Text = Trim(txtPassword.Text)
If txtPassword.Text = "" Then
   MsgBox " 请输入密码！"
   Exit Sub
End If

Dim msg, style, title, response

Dim Conn As New ADODB.Connection     '声明并实例化连接数据库对象 -- 用来连接数据库文件，并对数据库以及数据表的操作
Dim Rst As New ADODB.Recordset       '声明并实例化数据记录集对象 -- 用来返回数据记录集，并对记录的操作

'执行 ADODB.Connection对象的Open方法，完成数据库的连接
Conn.Open SQLConnecTionString1

'执行 ADODB.Recordset对象的Open方法，获得记录集
Rst.Open "Select * From 用户 Where 用户名='" & txtUserName.Text & "'", Conn, adOpenKeyset, adLockPessimistic
If Not (Rst.RecordCount >= 1) Then
   MsgBox "数据表记录为0！"
   End
End If

If Not (Rst.EOF And Rst.BOF) Then
   '检查正确的密码
   If Rst.Fields("密码") = txtPassword.Text Then
      Unload Me
      Form1.Show
   Else
      msg = "错误的登录密码！" & Chr(13) & Chr(10) & Chr(13) & Chr(10)
      style = vbRetryCancel + vbExclamation + vbDefaultButton1
      title = "提示"
      response = MsgBox(msg, style, title)
      If response = vbRetry Then
         Exit Sub
      ElseIf response = vbCancel Then
         End
      End If
   End If
Else
   msg = "错误的用户名！" & Chr(13) & Chr(10) & Chr(13) & Chr(10)
      style = vbRetryCancel + vbExclamation + vbDefaultButton1
      title = "提示"
      response = MsgBox(msg, style, title)
      If response = vbRetry Then
         Exit Sub
      ElseIf response = vbCancel Then
         End
      End If
End If

End Sub

新人求帮助