Error de lectura porque no hay datos

Hola a todos:

Tengo el siguiente codigo:

Private Sub txtCP_LostFocus(ByVal sender As Object, ByVal e As
System.EventArgs) Handles txtCP.LostFocusTry



Dim oCP As New SqlConnection

Dim cont As Integer

oCP.ConnectionString =
"Server=(local);Database=video;Trusted_Connection=True;"

Dim oComandcp As New SqlCommand("Select * from cp where cp='" &
Me.txtCP.Text & "'", oCP)

Dim oDatacp As SqlDataReader

oCP.Open()

oDatacp = oComandcp.ExecuteReader

oDatacp.Read()

If (oDatacp.IsDBNull("cp")) Then

MsgBox("Codigo no registrado", MsgBoxStyle.Question +
MsgBoxStyle.OKCancel, "No existente")

oCP.Close()

oDatacp.Close()

Else

Me.txtPoblacion.Text = oDatacp("poblacion")

Me.txtProvincia.Text = oDatacp("provincia")

oCP.Close()

oDatacp.Close()

End If

Catch ex As Exception

MsgBox(ex.Message)

End Try

End Sub