How to get Hidden Column Value in GridView

        protected void btnSelect_Click(object sender, EventArgs e)
        {
 
            Button btn = (Button)sender;
            DataControlFieldCell dfc = (DataControlFieldCell)btn.Parent;
            GridViewRow gvr = (GridViewRow)dfc.Parent;
            Label lblAddressId = (Label) gvr.FindControl("lblAddressId");
 
            int iAddressId = (int)  lblAddressId.Text;
            lstAddressId.Add(iAddressId);
 
        }