VB用户类型未定义，怎么搞，我不会呀。

Dim mrc As ADODB.Recordset（提示这里出错了呀，我不会VB呀，）

Private Sub Command1_Click()
mrc.MoveFirst
Call viewData
End Sub

Private Sub Command2_Click()

mrc.MovePrevious
If mrc.BOF Then
MsgBox "已经是第一条记录！", vbOKOnly + vbExclamation, "警告!"
mrc.MoveFirst
End If
Call viewData
End Sub

Private Sub Command3_Click()

mrc.MoveNext
If mrc.EOF Then
MsgBox "已经是最后一条记录！", vbOKOnly + vbExclamation, "警告!"
mrc.MoveLast
End If
Call viewData
End Sub

Private Sub Command4_Click()
mrc.MoveLast
Call viewData

End Sub

Private Sub Command5_Click()
Unload Me
End Sub

Private Sub Form_Load()
Left = (Screen.Width - Width) \ 2
Top = (Screen.Height - Height) \ 2
Dim txtSQL As String