c# - Understanding System.Threading.Tasks behavior -

i trying performance optimization using tasks take advantage of parallel threading in .net 4.0.

i have made 3 methods returns collections of objects or object. lets call them methoda, methodb , methodc.

inside of methodb have long-running delay - approximately 5-7 sec.

var person = new person();  person.a = task.factory.startnew(() => mystatic.methoda()).result; person.b = task.factory.startnew(() => mystatic.methodb()).result; person.c = task.factory.startnew(() => mystatic.methodc()).result; 

now expecting person.a , person.c properties set / populated before person.b, have difficulties testing / debugging verify assumptions.

i have added parallel watch on 3 properties, debugging through not clarifying things me.

also proper way me optimize multiple calls methods, if populating main object?

in case have 5-7 different methods gather data from, , make them parallel of them relatively time-consuming.

your assumption wrong. result property of task wait task complete - so, a, b , c assigned in sequence. also, defeat purpose of creating async tasks.

one way can use task.waitall on 3 tasks , assign result each task a,b,c

you can use async/await if have vs2012 - can still target .net 4.0 using http://nuget.org/packages/microsoft.bcl.async/

however understand async/await not start 3 tasks in parallel if this:

person.a = await task.run(() => mystatic.methoda()); person.b = await task.run(() => mystatic.methodb()); person.c = await task.run(() => mystatic.methodc()); 

it still sequential - if want parallel execution degree can this:

task ta = task.run(() => mystatic.methoda()); task tb = task.run(() => mystatic.methodb()); task tc = task.run(() => mystatic.methodc());  person.a = await ta; person.b = await tb; person.c = await tc;