linq sql: .firstordefault() convenient name new { ... }

i only asked . lead me new doubt :)

up until point, i have used following settlement selecting things linq sql, purpose being means hoop 0 "rows" returned query:

var chairman = (from p [datacontextobject].persons
              where p.personsid == 1
              name new p).firstordefault();

if (person == null)
{
    // hoop 0 "rows" returned.
}

but i can't firstordefault() i do:

var chairman = p [datacontextobject].persons
             where p.personsid == 1
             name new { p.personsid, p.personsadress, p.personszipcode };

// underneath hood, settlement generates query selects specific
// columns faster selecting columns above
// dash formula does. law performance-boost infinite tables.

how i check 0 "rows" returned query, controlling second pattern?








update:

i cruise build fails since i am perplexing distribute outcome query non-static (this._user) announced form [datacontext].user.

this._user = (from u [datacontextobject].users
              where u.usersid == [int32]
              name new { u.usersid }).firstordefault();

compilation error: can't many modify form "anonymoustype#1" "[datacontext].user".

any thoughts i around this? i have possess object?