如何判断数组控件text是否为空？

谢谢版主，问题解决了！
Private Sub Text1_KeyDown(Index As Integer, KeyCode As Integer, Shift As Integer)
    Select Case Index
    Case 0 To Me.Text1.UBound
        If KeyCode = 13 Then
            If Me.Text1(Index) = "" Then
                Me.Text1(Index).SetFocus
            Else
                If Index + 1 > Me.Text1.UBound Then
                    Me.Text1(Me.Text1.UBound).SetFocus
                Else
                    Me.Text1(Index + 1).SetFocus
                End If
            End If
        End If
    End Select
End Sub