.NET Already Open DataReader - asp.net

Question

I get this error when running this code. I have looked for solution though I don't like the idea of using MARS as people have suggested as it may contain a lot of data, is there any other option here? Also can I edit a variable in a database without rewriting all of them as I do here, will this save server power or make no difference?
There is already an open DataReader associated with this Command which must be closed first.
public ActionResult CheckLinks(Link model)
{
var userId = User.Identity.GetUserId();
var UserTableID = db.UserTables.Where(c => c.ApplicationUserId == userId).First().ID;
foreach (var item in db.Links.Where(p => p.UserTable.ID == UserTableID))
{
string pageContent = null;
HttpWebRequest myReq = (HttpWebRequest)WebRequest.Create(item.Obdomain);
HttpWebResponse myres = (HttpWebResponse)myReq.GetResponse();
using (StreamReader sr = new StreamReader(myres.GetResponseStream()))
{
pageContent = sr.ReadToEnd();
}
string live = "";
if (pageContent.Contains(item.Obpage))
{
live = "Yes";
}
else { live = "No"; }
var link = new Link { Obdomain = item.Obdomain, ClientID = item.ClientID, Obpage = item.Obpage, BuildDate = item.BuildDate, Anchor = item.Anchor, IdentifierID = item.IdentifierID, live = (Link.Live)Enum.Parse(typeof(Link.Live), live), UserTableID = item.UserTableID };
db.Entry(link).State = EntityState.Modified;
db.SaveChanges();
}
return RedirectToAction("Index");
}

Answer 1

Entity Framework allows only one active command per context at a time. You should add .ToList() at the end of the following statement:
db.Links.Where(p => p.UserTable.ID == UserTableID).ToList();
So your code could look like this:
var items = db.Links.Where(p => p.UserTable.ID == UserTableID).ToList();
foreach (var item in items)