How to Put the data in session

protected void Page_Load(object sender, EventArgs e)
    {
        SqlConnection cn = new SqlConnection("user id=sa;password=123;database=mydatabase;data source=.");
        SqlDataAdapter da = new SqlDataAdapter("select * from employee", cn);
        DataSet ds = new DataSet();
        da.Fill(ds,"emp");
        GridView1.DataSource = ds.Tables[0];
        GridView1.DataBind();
        Session["mydata"]=ds;
    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        Response.Redirect("getSessionDb.aspx");
    }







 protected void Page_Load(object sender, EventArgs e)
    {
        DataSet ds = new DataSet();
        ds=(DataSet)Session["mydata"];
        GridView1.DataSource = ds.Tables[0];
        GridView1.DataBind();
        DetailsView1.DataSource = ds.Tables[0];
        DetailsView1.DataBind();
    }
}