LINQ Take() returns the same results over and over

Question

I want to page over some records but the Take() extension from LINQ isn\'t returning the result which I expected.

public IQueryable<         


        

Answer 1

.Take returns the specified number of results on a query, and if it is the same query it will often return the same results. To resolve this, you might use a combination of .Skip and .Take, changing the number you are Skipping and Takeing each time.

private int counter = 0;
public IQueryable GetPersonBetweenDates(DateTime start, DateTime end)
{
    var results = dbcontext.Persons.Where(x => x.RegisterDate >= start && x.RegisterDate <= end).Skip(counter).Take(20);
    counter += 20;
    return results;
}

Keep in mind that you will be able to call this continuously, even after there are no more records.

Alternatively, you could cache the query (if you aren't reinstantiating the class on each use):

private IQueryable qry = dbcontext.Persons.Where(x => x.RegisterDate >= start && x.RegisterDate <= end);
public IQueryable GetPersonBetweenDates(DateTime start, DateTime end)
{
    qry = qry.Skip(20);
    return qry.Take(20);
}

Nevertheless, both of these snippets may have other issues -- see tvanfosson's comments and answer.