c# - How to use BackgroundWorker with custom Progress Dialog (Form with ProgressBar)? -

i've got method loads files. takes lot of time show user progressbar window, can minimize whole application or cancel progress.

i've read bunch of tutorials backgroundworkers , progressbars none of these covers scenario, when progressbar @ other form. don't know when should open new form , how access progress bar there.

so far i've tried:

mainform:

private void addfoldertoolstripmenuitem_click(object sender, eventargs e) {     ctlfolderselectdialog dlg = new ctlfolderselectdialog();     if (dlg.showdialog() == dialogresult.ok)     {         backgroundworker.runworkerasync(dlg); // pass variables ctlfolderselectdialog     } }  private void backgroundworker_dowork(object sender, doworkeventargs e) {     form_dialogs.progressdialog progressdialog = new form_dialogs.progressdialog();     progressdialog.showdialog(); // open progress dialog window      myclass.loadfiles((ctlfolderselectdialog)e.argument); // work      progressdialog.close(); // close progress window - in here? } 

myclass:

public void loadfiles(ctlfolderselectdialog dlg) {     ...     files.count() // somehow report preliminary number of files progressbar window - set progressbar1.maximum value     ...     foreach (file in files)     {         loadfile();         ... // here should somehow udpate progressbar on other window - performstep()     } } 

progressdialog:

private void progressdialog_load(object sender, eventargs e) {     progressbar1.value = 0;     progressbar1.maximum = 100; // how value myclass function? pass in progressdialog contructor?     progressbar1.step = 1; }  public void updateprogress(int progress) {     progressbar1.performstep(); } 

backgroundworker supports progress updates through progresschanged event.

inside loadfiles() method need calculate progress in % , inside foreach loop call backgroundworker.reportprogress(percentage). raise progresschanged event can in event arguments e.progresspercentage. [you need reference backgroundworker inside loadfiles() method]

in progressdialog form need register event. can pass backgroundworker in constructor e.g.

public void progressdialog(backgroundworker worker) {    worker.progresschanged += progressdialog_progresschanged; }  private void progressdialog_progresschanged(object sender, progresschangedeventargs e) {    updateprogressbar(e.progresspercentage); } 

and in main form:

private void addfoldertoolstripmenuitem_click(object sender, eventargs e) {     ctlfolderselectdialog dlg = new ctlfolderselectdialog();     if (dlg.showdialog() == dialogresult.ok)     {         backgroundworker.runworkerasync(dlg); // pass variables fromctlfolderselectdialog         form_dialogs.progressdialog progressdialog =             new form_dialogs.progressdialog(backgroundworker); // pass backgroundworker instance         progressdialog.showdialog(); // open progress dialog window         // no need explicitly close it. dialog form destroyed when closed user.     } }  private void backgroundworker_dowork(object sender, doworkeventargs e) {     myclass.loadfiles((ctlfolderselectdialog)e.argument); // work }