c# - Adding a default string if list empty -

i'm writing out aggregated list of statuses. works fine except situation there none. @ moment, null rendered , position empty.

item.stuff.where(e => condition(e))   .select(f => f.status)   .aggregate(string.empty, (a, b) => + b) 

now, i'd populate table element "---" in case list filtered down empty 1 condition can't decide on method.

what smooth way approach it?

i've tried atrocity below looks, well..., atrociously , doesn't render right, neither. see actual source code line (preceded false or true) instead of values.

item.stuff.where(e => condition(e)).count() < 1   ? "---"   : item.stuff.where(e => condition(e))     .select(f => f.status)     .aggregate(string.empty, (a, b) => + b) 

you this. if status list reasonably small (otherwise 1 should use stringbuilder anyway , not string concatenation).

item.stuff.where(e => condition(e))     .select(f => f.status)     .aggregate("---", (a, b) => (a == "---") ? b : (a + b)); 

it checks if default text replaced and, if was, concatenates next status element existing text mass.

this return "---" if , if it's never evaluated, i.e. if list empty. otherwise 1 same result previously.

---

if status enum, , need distinct statuses, can use behavior of [flags] attribute.

if define enum this

[flags] enum status {     none = 0,     active = 1,     inactive = 2,     pending = 4,     deleted = 8     ... } 

you can do:

item.stuff.where(e => condition(e))   .aggregate(status.none, (a, b) => | b) 

the result collection of statuses present in list, , output nicely formatted list (active, inactive, pending) or none if it's never run.