Forms Data Controls :: Sorting Data With Gridview?

Actually i am using procedures and calling them using linq.I have a gridview and there is no data source bound to it in aspx page.I am binding different procedures with gridview in code behind.I am feeling myself unable to sort the data.

here is my code on page load event

if (Request.QueryString["Id"] != null)
{
if (Request.QueryString["Id"].ToString() == "0")
{
var list = db.prcSelectTodayNewListing();
gvListing.DataSource = list;
gvListing.DataBind();
}
else if (Request.QueryString["Id"].ToString() == "")
{
var list = db.prcSelectListing();
gvListing.DataSource = list;
gvListing.DataBind();
}
else
{
var list = db.prcSelectListingByStatusId(Convert.ToInt32(Request.QueryString.Get("Id")));
gvListing.DataSource = list;
gvListing.DataBind();
}
}