how to store id with in sessions

ex1.

LinkButton lnkbtn = sender as LinkButton;

        GridViewRow gvrow = lnkbtn.NamingContainer as GridViewRow;

        int id = Convert.ToInt32(gv_addsolution.DataKeys[gvrow.RowIndex].Value);

        Session["id"] = id.ToString();

ex2.

session["id"]=txtid.text;
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after that session["id"] retriving any time if you want, see below

int id = Convert.ToInt32(Session["id"]);