c# - Run simultaneous tasks after a BackgroundWorker has completed -

i'm using backgroundworker stream text file in backgorund.

when completed want run 2 simultaneous tasks involve 2 methods heavy calculations. these methods used streamed data calculations.

somehow i've been stuck. first part executed , i'm able stream data. second part involving calculations doesn't execute.

private readonly backgroundworker _streamworker = new backgroundworker();  public mainwindow() {     initializecomponent();      _streamworker.workerreportsprogress = true;     _streamworker.workersupportscancellation = true;      _streamworker.dowork += streamdata;     _streamworker.runworkercompleted += worker_runworkercompleted;     _streamworker.runworkerasync(); }  private void streamdata(object sender, doworkeventargs e) {     // stream text file here }  private void worker_runworkercompleted(object sender, runworkercompletedeventargs e) {     var task1 = task.factory.startnew(heavymethod1);     var task2 = task.factory.startnew(heavymethod2);      task.waitall();      // after calculations have ended     // calculate results here }  private void heavymethod1() {     // heavy calculations } private void heavymethod2() {     // heavy calculations not      // related ones in heavymethod1 } 

update: 1 very odd thing have noticed if put messagebox.show(""); before calculations works fine!

private void worker_runworkercompleted(object sender, runworkercompletedeventargs e) {     var task1 = task.factory.startnew(heavymethod1);     var task2 = task.factory.startnew(heavymethod2);      task.waitall();     messagebox.show("");      // after calculations have ended     // calculate results here } 

you don't wait anything. use task1 , task2

task.waitall(new task[]{task1, task2}); 

update

with messagebox, give chance tasks complete works.