c# - IAsyncresult - polling without freezing the UI? -

i've got windows svc running asynchronously (i've edited methods , parameters make them async), little like: http://msdn.microsoft.com/en-us/library/ms731177.aspx

however, call task want run asynchronously (the call service/server), , update ui (using reportprogress() on backgroundworker - of happening in dowork() method of backgroundworker). however, call endxxx method results, problem is, shouldn't code like?

while (!asyncresult.iscompleted) { // ui updating etc here... }  // call endxxx here. 

however, approach locks ui. @ moment, code (and doesn't lock ui):

 iasyncresult res = null;                  try                 {                      res = servicex.beginxxx(resultcallback, "");                 }                 catch (faultexception<managementexception> managementex)                 {                     logger.error(managementex.detail.tostring());                     messagebox.show("could not add printer. see log.");                 }                        installbackgoundworker.reportprogress(90);                     installbackgoundworker.reportprogress(91);                     installbackgoundworker.reportprogress(93);                      installbackgoundworker.reportprogress(94);                     installbackgoundworker.reportprogress(95);                     installbackgoundworker.reportprogress(96);                     installbackgoundworker.reportprogress(97);                        if (res.iscompleted)                     {                         resultcallback(res);                     }                     installbackgoundworker.reportprogress(100); 

is correct? seems wrong me.

i'm not you're using async pattern correctly. should this:

void start() {     system.io.stream s = ...;     byte[] buf = ...;      // start io.      s.beginread(buf, 0, buf.length, res =>         {             // gets called when it's finished,             // you're in different thread.              int len = s.endread(res);              // must call dispatcher.invoke             // ui thread.              dispatcher.invoke((action)delegate                 {                     // perform ui updates here.                 });         }, null);      // io started (and maybe finished) here,     // don't need put here. } 

written stream because don't know signature of object, idea! need process completion of operation in callback give it, not directly after call begin method. shouldn't need poll iscompleted property.