multithreading - bind log Asynchronous in winForm c# -

i tried add log inside winform while doind something

    private async task savechunk(datachunksaver chunk)     {         int = 0;         int step = 10;          while (chunk.savechunk(i, step))         {             += step;             addlog(chunk.log);         }     } 

where:

    private async task addlog(string text)     {         logbulider.appendline(text);          logbox.text = logbulider.tostring();     } 

andlogbulider simple global stringbulider. problem when fire button savechunk task form freezes, can see logbox after done , wanned bisplayed after each step of chunk.savechunk.
tried fire them few methods, can't handle it

what doing wrong?

        private async void button2_click(object sender, eventargs e)             {     await task.factory.startnew(() => savechunk(chunk));     task t = savechunk(chunk);     // none of these works, tried few other //ways it, none prevents winform freezing         } 

i tried modify code using progress<string>:

private async void button2_click(object sender, eventargs e) {     var progress = new progress<string>(msg =>     {      logbulider.appendline(msg);      logbox.text = logbulider.tostring();     });     await task.run(() => savechunk(chunk, progress)); } 

and

private async task savechunk(datachunksaver chunk, iprogress<string> progress) {     int = 0;     int step = 10;      while (chunk.savechunk(i, step))     {         += step;         progress?.report(chunk.log); // use progress if null!     } }