Delete query in Linq

Question

I have this simple code but it shows error. I dont know where I am going wrong. I shows error in last line.."DeleteOnSubmit" linq_testDataContext db = new linq_testDataContext();

var remove = from aremove in db.logins
         where aremove.username == userNameString && aremove.Password == pwdString
         select aremove;
db.logins.DeleteOnSubmit(remove);

Thanks, Ani

Answer 1

DeleteOnSubmit takes a single object. You are passing an IEnumerable<login> to it. Use DeleteAllOnSubmit instead, or select a single object from your resulting collection, like this:

var remove = (from aremove in db.logins 
             where aremove.username == userNameString 
                && aremove.Password == pwdString 
             select aremove).FirstOrDefault(); 

if(remove != null)
{
    db.logins.DeleteOnSubmit(remove);
}

Answer 2

Instead of:

db.logins.DeleteOnSubmit(remove);

Call DeleteAllOnSubmit(), like this:

db.logins.DeleteAllOnSubmit(remove.ToList());

Make sure to call db.SubmitChanges() afterwards. You could use .AsEnumerable() as well, either or. If it's a large delete operation though, you may want to think about bypassing LINQ in this case.