.net - vb net update UI controls from separate thread event -

i have 1 class called sftpconnectormanager.vb responsible managing ftp connections server. have form1.vb class main gui. want update progressbar resides on form1 show progress of file transfer. function responsible initiating connection ftp server started on new thread, allows form1 not frozen, good, challenge me being able update progress bar, not working out me @ all.

what have tried/done:

1. using delegate update ui separate thread
2. using background worker , using it's progress changed event, thought might on here remembered update ui needs happen during file transfer event, sessionfiletransferprogress, not when raise progress changed event.
3. read on 20 pages worth of documentation in regards multi-threading , event handling, still don't understand guess...

what need happen:

4. updates progress bar ui control, update while file transfer in progress, , needs not freeze ui, needs running on separate thread (which have achieved far believe)

code using:

1. https://winscp.net/eng/docs/library_session
2. https://winscp.net/eng/docs/library_session_filetransferprogress

form1.vb

 public sub sub1(byval x integer, y integer)     statuslabel2.text = "connected"     progressbar1.maximum = progressbar1.maximum + x     progressbar1.value = progressbar1.value + y  end sub  private sub button1_click(sender object, e eventargs) handles startbtn.click     '    if (backgroundworker1.isbusy) <> true     '        backgroundworker1.runworkerasync()     '    end if      'call xml reader respective values , store them class property      dim oconnect = new sftpconnectormanager     dim oxmlread xmlreader = xmlreader.create("d:\dale_documents\projects\programming\vbnet\remote_data_backup\sftp_backup\settings.xml")      while (oxmlread.read())          dim etype = oxmlread.nodetype          if (etype = xmlnodetype.element)              if (oxmlread.name = "hostname")                 oconnect.hostname = oxmlread.readinnerxml.tostring             end if              if (oxmlread.name = "username")                 oconnect.username = oxmlread.readinnerxml.tostring             end if              if (oxmlread.name = "password")                 oconnect.password = oxmlread.readinnerxml.tostring             end if              if (oxmlread.name = "port")                 oconnect.port = oxmlread.readinnerxml.tostring             end if              if (oxmlread.name = "protocol")                 oconnect.protocolselection = oxmlread.readinnerxml.tostring             end if              if (oxmlread.name = "ftpmode")                 oconnect.ftpmodeselection = oxmlread.readinnerxml.tostring             end if              if (oxmlread.name = "sshfingerprint")                 oconnect.sshkey = oxmlread.readinnerxml.tostring             end if              if (oxmlread.name = "remotepath")                 oconnect.remotepath = oxmlread.readinnerxml.tostring             end if              if (oxmlread.name = "localpath")                 oconnect.localpath = oxmlread.readinnerxml.tostring             end if         end if      end while      dim eprotocoloptions = oconnect.protocolselection     dim susername = oconnect.username     dim shostname = oconnect.hostname     dim spassword = oconnect.password     dim ssshkey = oconnect.sshkey     dim iport = oconnect.port     dim sremotepath = oconnect.remotepath     dim slocalpath = oconnect.localpath     dim bflag = oconnect.bflag       dim asoptions = new string() {eprotocoloptions, shostname, susername, iport, spassword, ssshkey, sremotepath, slocalpath}      oconnect.testthread(asoptions) 

sftpconnectormanager.vb

function startconnectionthread(asoptions)      try         dim osessionoptions new sessionoptions         osessionoptions             .protocol = protocolselection             .hostname = hostname             .username = username             .portnumber = port             .password = password             .sshhostkeyfingerprint = sshkey         end          using osession new session             addhandler osession.filetransferprogress, addressof sessionfiletransferprogress             osession.open(osessionoptions)              dim otransferoptions new transferoptions             otransferoptions.transfermode = transfermode.binary              osession.getfiles(remotepath, localpath, false, otransferoptions)              osession.close()              bflag = false         end using          messagebox.show("file transfer compelete")          return 0     catch ex exception         messagebox.show(ex.tostring())         return 1     end try  end function   public delegate sub setbarvalues(maximum integer, value integer) private sub sessionfiletransferprogress(byval sender object, byval e filetransferprogresseventargs)       dim oform1 = form1     dim msd setbarvalues = addressof oform1.sub1      if oform1.invokerequired         msd.invoke(1, 1)     else         oform1.sub1(1, 1)     end if      'oform1.progressupdate()      'if (form1.checkforillegalcrossthreadcalls)     '    msgbox("illegal cross-thread operation deteced.")     'end if   end sub  public sub testthread(asoption())     dim osftpconnectionmanager = new sftpconnectormanager     dim thread new thread(addressof osftpconnectionmanager.startconnectionthread)      osftpconnectionmanager.protocolselection = asoption(0)     osftpconnectionmanager.hostname = asoption(1)     osftpconnectionmanager.username = asoption(2)     osftpconnectionmanager.port = asoption(3)     osftpconnectionmanager.password = asoption(4)     osftpconnectionmanager.sshkey = asoption(5)     osftpconnectionmanager.remotepath = asoption(6)     osftpconnectionmanager.localpath = asoption(7)      thread.start()  end sub 

so may see tried use delegate, did fair bit of reading on , believe need update ui elements separate thread, have misunderstood because can't implement concept in own project. ui changes needs happen during sessionfiletransferprogress event.

please guys , girls @ wits end this, final saving grace , don't think able continue learning program if can't understand , implement these concepts.

here simple example shows concepts. has class has long running (sic) activity wants report progress ui. you'll need form 2 buttons, progressbar, , textbox. hope helps conceptually.

public class form1      private sub button1_click(sender object, e eventargs) handles button1.click         progressbar1.value = 0         dim foo new someclass(new action(addressof showprog))         foo.simulateactivity() 'long running         button2.select()     end sub      public sub showprog()         if me.invokerequired ' on ui?             me.invoke(sub() showprog()) ' no, run on ui         else             progressbar1.increment(1) ' yes, on ui         end if     end sub      private sub button2_click(sender object, e eventargs) handles button2.click         'test if ui available while long running         'press button 2 while long running confirm ui         textbox1.text = progressbar1.value.tostring     end sub end class  public class someclass      private _action action     public sub new(progress action)         me._action = progress     end sub      public sub simulateactivity()         'runs on thread         dim t task         t = task.run(sub()                          x integer = 1 100                              me._action()                              threading.thread.sleep(50)                          next                      end sub)     end sub end class