How to get current user ID - asp.net

Question

I'm developing a web page and when you sign up and login you need to complete your information (name, last name, career, gender).
I've created a stored procedure:
ALTER PROCEDURE [dbo].[añadirinfocontacto]
#id int,#apellidoP nvarchar(50),#apellidoM nvarchar(50),#nombre nvarchar(50),#idEspecialidad int,#sexo nvarchar(10)
AS
BEGIN
if(#id=1)
begin
update Tbl_alumnos set nombre=#nombre,apellido_paterno=#apellidoP,apellido_materno=#apellidoM,id_especialidad=#idEspecialidad,sexo=#sexo where id_usuarios=#id
end
else
if(#id=2)
begin
update Tbl_Maestros set nombre=#nombre,apellido_paterno=#apellidoP,apellido_materno=#apellidoM,id_especialidad=#idEspecialidad,sexo=#sexo where id_usuarios=#id
end
else
begin
update Tbl_Administradores set nombre=#nombre,apellido_paterno=#apellidoP,apellido_materno=#apellidoM,id_especialidad=#idEspecialidad,sexo=#sexo where id_usuarios=#id
end
END
Code:
public static EntUsuario Actualizar(int idU,string nombre, string Apellidop,string ApellidoM,int IdEsp,string sexo)
{
EntUsuario obj = null;
SqlCommand cmd = null;
SqlDataReader dr = null;
try
{
Conexion cn = new Conexion( );
SqlConnection cnx = cn.conectar();
cmd = new SqlCommand("añadirinfocontacto", cnx);
cmd.Parameters.AddWithValue("#id", idU);
cmd.Parameters.AddWithValue("#nombre", nombre);
cmd.Parameters.AddWithValue("#apellidoP", Apellidop);
cmd.Parameters.AddWithValue("#apellidoM", ApellidoM);
cmd.Parameters.AddWithValue("#idEspecialidad", IdEsp);
cmd.Parameters.AddWithValue("#sexo", sexo);
cmd.CommandType = CommandType.StoredProcedure;
cnx.Open();
cmd.ExecuteNonQuery();
cnx.Close();
}
catch (Exception e)
{
obj = null;
}
finally
{
cmd.Connection.Close();
}
return obj;
}
And the Cick button event
protected void btnConfirmar_Click(object sender, EventArgs e)
{
Guid guid = (Guid)Membership.GetUser().ProviderUserKey;
EntUsuario obj = GbUsuario.Actualizar(Convert.ToInt32(guid),txtNombre.Text,txtApP.Text,txtApM.Text,Convert.ToInt32(dpEspecialidad.SelectedValue),RadioButtonList1.SelectedValue);
}
I want to get de user's ID but I don't know what to do, I've read about Session["user_id"], Membership.getUser, I also read that I need to configure web.config.
If I use the sample code above I use Membership.getUser but appears an error saying that it couldn't conect to database

Answer 1

enter code hereYou can get the current user with the following code:
var user = System.Web.HttpContext.Current.User
You can force users to log in by adding this to the web.config:
<configuration>
<system.web>
<authentication mode="Windows" />
<authorization>
<deny users="?"/>
</authorization>
</system.web>
</configuration>