adding functonality linq-to-sql objects perform common selections

in i asked "computed properties" linq sql object. answer reputed there sufficient specific box nonetheless i've strike identical separator another case.

i have database items have pass by array steps. i wish have duty database retrieves tide step vigilant i following build on. example:

var x = db.items.where(item => item.steps.currentstep().completed == null);

the formula tide step is:

steps.orderbydescending(step => step.created).first();

so i attempted supplement an progression slight entityset<step> returned unparalleled step so:

public stationary orderflowitemstep currentstep(this entityset<orderflowitemstep> steps)
{
    relapse steps.orderbydescending(o => o.created).first();
}

but i try govern query during tip i an blunder observant currentstep() duty interpretation sql. there proceed supplement functionality linq-to-sql any proceed i have manually query each time? i attempted whole query out initial nonetheless it's unequivocally enlarged i ever change proceed active step an vigilant i have over formula again.

i'm guessing currentstep() slight relapse linq countenance kind nonetheless i'm stranded exercise it.