Error getting the DataKeryName in GridViewRow VB .NET

Recently, I had to maintain a system that is developed in Visual Basic. Net, and the truth is that this crazy, you see, my problem is this, I have a GridView:

<asp:GridView ID="GvwTrack" runat="server" AutoGenerateColumns="False" CellPadding="4"
 EmptyDataText="[No se ha registrado un Track]" ForeColor="#333333" GridLines="None"
 TabIndex="65" Width="100%" DataKeyNames="LoteTrackId,TipoTrackId">
 <Columns>
 <asp:CommandField SelectText="Borrar" ShowSelectButton="True" />
 <asp:BoundField DataField="LoteTrackId" HeaderText="ID" Visible="False" />
 <asp:BoundField DataField="Tracking" HeaderText="TRACK">
 <ItemStyle Width="100px" />
 </asp:BoundField>
 <asp:BoundField DataField="Sitio" HeaderText="SITIO">
 </asp:BoundField>
 <asp:BoundField DataField="Mensajero" HeaderText="MENSAJERO">
 <ItemStyle Width="150px" />
 </asp:BoundField>
 <asp:BoundField DataField="Responsable" HeaderText="RESPONSABLE">
 <ItemStyle Width="150px" />
 </asp:BoundField>
 <asp:BoundField DataField="Fecha" HeaderText="FECHA" DataFormatString="{0:d}">
 <ItemStyle Width="120px" />
 </asp:BoundField>
 <asp:BoundField DataField="Hora" DataFormatString="{0:t}" HeaderText="HORA">
 <ItemStyle Width="80px" />
 </asp:BoundField>
 </Columns>
 </asp:GridView>

In the codeBeside the gridView is filled through a Sub and up to here everything is fine, the information shows correctly in the table

Sub CargarListaTracking()
        Dim ListaTracking As New DataTable
        Dim ConsultarTracking As New SqlCommand("SELECT [LoteTrackId], [TipoTrackId], [Sitio], [Responsable], [Mensajero], [Fecha], [Hora], " _
                                               & " (CASE WHEN TipoTrackId = '1' THEN  'Recolección' " _
                                               & " WHEN TipoTrackId = '2' THEN 'Devolución' " _
                                               & " WHEN TipoTrackId = '3' THEN 'Enlace de Mensajería' " _
                                               & " WHEN TipoTrackId = '4' THEN 'Entrega Parcial' " _
                                               & " WHEN TipoTrackId = '5' THEN 'Entrega Final' END) AS Tracking " _
                                               & " FROM [OperacionesTracking]  " _
                                               & " WHERE ([IdGuia] = @IdGuia)  " _
                                               & " ORDER BY [Fecha], [Hora]")
        ConsultarTracking.Parameters.AddWithValue("@IdGuia", HdnIdGuia.Value)
        ConsultarTracking.Connection = C.Conecta_Albatros

        C.Data_Adapter = New SqlDataAdapter(ConsultarTracking)
        C.Data_Adapter.Fill(ListaTracking)

        GvwTrack.DataSource = ListaTracking
        GvwTrack.DataBind()
    End Sub

You have a Sub SelectedIndexChanged in which you need to obtain a DataKey data pair from the GridView: LoteTrackId and TipoTrackId

Protected Sub GvwTrack_SelectedIndexChanged(sender As Object, e As EventArgs) Handles GvwTrack.SelectedIndexChanged
        Dim LoteTrackId As Integer = Convert.ToInt32(GvwTrack.DataKeys(GvwTrack.SelectedIndex).Value(0))
        Dim TipoTrackId As Byte = Convert.ToByte(GvwTrack.DataKeys(GvwTrack.SelectedIndex).Value(1))

        .... Mas codigo

    End Sub

When executing it, it throws me an error, in which it marks line 168, which is where I try to recover the LoteTrackId and it says the following:

Error de servidor en la aplicación '/'.
No se encontró ningún miembro predeterminado para el tipo 'Integer'.
Descripción: Excepción no controlada al ejecutar la solicitud Web actual. Revise el seguimiento de la pila para obtener más información acerca del error y dónde se originó en el código. 

Detalles de la excepción: System.MissingMemberException: No se encontró ningún miembro predeterminado para el tipo 'Integer'.

Error de código fuente: 


Línea 166:
Línea 167:    Protected Sub GvwTrack_SelectedIndexChanged(sender As Object, e As EventArgs) Handles GvwTrack.SelectedIndexChanged
Línea 168:        Dim LoteTrackId As Integer = Convert.ToInt32(GvwTrack.DataKeys(GvwTrack.SelectedIndex).Value(0))
Línea 169:        Dim TipoTrackId As Byte = Convert.ToByte(GvwTrack.DataKeys(GvwTrack.SelectedIndex).Value(1))
Línea 170:

I have been trying to solve this all day and I do not understand what is wrong, I have consulted several forums and pages, it is assumed that the DataKeys query is correct, I hope you can help me, in advance, thanks.