If GridViewRow Is Selected Then - Else

I have an IfThen Statement that states if a row is selected, then execute, else, display message. The code runs fine if I select a row, however when I try and proceed without selecting a row I get an error instead of the message I want to display.

Here is an example of what I'm trying to do:
Protected Sub btnReplace(ByVal sender As Object, ByVal e As EventArgs)
Dim row As GridViewRow = device_list.SelectedRow
If (row.RowState Or DataControlRowState.Selected) > 0 Then
Message.Text = "You selected " & row.Cells(1).Text & "."
Else
Message.Text = "Please select a device."
End If
End Sub