刚学的VBA，运行提示未获得焦点，请高手帮忙看一下，要怎么改。
Private Sub cmd_登录_Click()
Dim objcon As New ADODB.Connection
Dim strConn As String
Dim dat As String
'Connect the database
strConn = "Provider=SQLOLEDB.1;User ID=sa;password=*****;Initial Catalog=********;Data Source=********"
objcon.Open strConn
Dim rsPubs As ADODB.Recordset
Set rsPubs = New ADODB.Recordset
If Trim(txt_用户名.Text) = "" Then '检查用户名是否为空
DoCmd.Beep
MsgBox "用户名和密码不能为空，请重新输入！", vbOKOnly + vbInformation, "提示信息"
Me.txt_用户名.SetFocus
Else
dat = "SELECT * FROM DSCMA WHERE MA001='" & txt_用户名.Value & "' AND MA003='" & txt_密码.Value & "'"
rsPubs.Open dat, conn
If Me.Recordset.EOF Then
DoCmd.Beep
MsgBox "用户名不存在，请重新输入！", vbOKOnly + vbExclamation, "错误"
txt_用户名 = ""
Me.txt_用户名.SetFocus
Else
If Trim(rsPubs.Fields(1)) = Trim(txt_密码) Then
rsPubs.Close
DoCmd.OpenForm "报表管理系统主窗体"
Else
MsgBox "密码错误，请重新输入！", vbOKOnly + vbExclamation, "错误"
txt_密码.SetFocus
End If
End If
End If
End Sub
