WebService

    [WebMethod]
    public DataSet consultarEmpleadosPubs()
    {

        String urlConexion = "Data Source=(local);AttachDbFilename='X:\\UTN\\2.2\\Laboratorio4\\Acceso a Datos\\PUBS.MDF';Integrated Security=True";
        SqlConnection conexion = new SqlConnection(urlConexion);
        SqlDataAdapter consulta = new SqlDataAdapter("SELECT * FROM employee", conexion);
        DataSet datos = new DataSet();
        consulta.Fill(datos);

        return datos;
    }

/////////////////////////////////////////////////////////////////
Este es el aspx q llama al consultarEmleadosPubs o el North...
/////////////////////////////////////////////////////////////////
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data.SqlClient;
using System.Data;

public partial class _Default : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {

    }

    protected void Button1_Click(object sender, EventArgs e)
    {
        WebService sw = new WebService();
        if (DropDownList1.SelectedValue == "DBNorthwind") //lee Northwind
        {
            GridView1.DataSource = sw.consultarEmpleadosNorthwind();
            GridView1.DataBind();
        }
        else //lee Pubs
        {
            GridView1.DataSource = sw.consultarEmpleadosPubs();
            GridView1.DataBind();
        }
    }
}