SingleOrDefault() throws an exception on more than one element

Question

I\'m getting an exception whenever I fetch like this

Feature f = o.Features.SingleOrDefault(e => e.LinkName == PageLink);

because this can r

Answer 1

Single and SingleOrDefault are designed to throw if more that one match exists in the sequence. A consequence of this is that the entire sequence must be iterated prior to completion. It does not sound like this is what you want. Try FirstOrDefault instead:

Feature f = o.Features
    .FirstOrDefault(e => e.vcr_LinkName == PageLink && e.bit_Activate == true);

This will (generally) perform better because it completes as soon as a match is found.

Of course, if you actually want to retain more than one element, a Where clause would be more appropriate:

IEnumerable fs = o.Features
    .Where(e => e.vcr_LinkName == PageLink && e.bit_Activate == true);