c# - Task.Factory.StartNew with async lambda and Task.WaitAll -

i'm trying use task.waitall on list of tasks. thing tasks async lambda breaks tasks.waitall never waits.

here example code block:

list<task> tasks = new list<task>(); tasks.add(task.factory.startnew(async () => {     using (dbcontext = new databasecontext())     {         var records = await dbcontext.where(r => r.id = 100).tolistasync();         //do long cpu process here...     } } task.waitall(tasks); //do more stuff here   

this doesn't wait because of async lambda. how supposed await i/o operations in lambda?

task.factory.startnew doesn't recognise async delegates there no overload accepts function returning task.

this plus other reasons (see startnew dangerous) why should using task.run here:

tasks.add(task.run(async () => ...