tengo un index.aspx (index.aspx.cs) que incluirá el body.aspx (body.aspx.cs) usando Server.exectue ("body.aspx");

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;
using System.Collections;

public partial class index : System.Web.UI.Page
{
    public string text1 = "abc";

    protected void Page_Load(object sender, EventArgs e)
    {


    }

}

en index.asp.cs, hay una variable text1 que quiero usar en body.aspx.cs, ¿cómo hacerlo?

Gracias