If the BackgroundWorker was created from the UI thread, then the RunWorkerCompleted event will also be raised on the UI thread. If it was created from a background thread, the event will be raised on an undefined background thread (not necessarily the same thread, unless you’re using a custom SynchronizationContext). Interestingly, this doesn’t seem to … Read more
You could use a closure (Lambda): backgroundWorker.DoWork += (s, e) => MyWorkMethod(userName, targetNumber); Or with delegate (anonymous method) syntax: backgroundWorker.DoWork += delegate(object sender, DoWorkEventArgs e) { MyWorkMethod(userName, targetNumber); };
Yes, you should dispose of the background worker. You may find it easier to use ThreadPool.QueueUserWorkItem(…) which doesn’t require any clean up afterwards. Additional detail on why you should always call Dispose(): Although if you look in the BackgroundWorker class it doesn’t actually do any thread clean up in it’s dispose method, it is still … Read more
The main difference between the Dispatcher and other threading methods is that the Dispatcher is not actually multi-threaded. The Dispatcher governs the controls, which need a single thread to function properly; the BeginInvoke method of the Dispatcher queues events for later execution (depending on priority etc.), but still on the same thread. BackgroundWorker on the … Read more
Let’s start with the API. I’d like to have something like the following. @available.working? # => true or false, so we know it’s running @available.finished? # => true or false, so we know it’s finished (already ran) Now let’s write the job. class AwesomeJob < Struct.new(:options) def perform do_something_with(options[:var]) end end So far so good. … Read more
The exception is not passed back to the calling thread. If you want it to be, you can add a catch block and figure out a way to signal the calling thread. If the calling thread is a WinForms or WPF UI thread, you can use the SynchronizationContext class to pass a call to the … Read more
Unfortunately you can’t. The compiler does not allow you to combine the two “magic” pieces of code. Both involve rewriting your code to support what you want to do: An anonymous method is done by moving the code to a proper method, and lifting local variables to fields on the class with that method An … Read more
As the error suggests, set the WorkerReportsProgress property of your BackgroundWorker component to true.
You need something like this: public delegate void ProgressChangeDelegate(double Percentage, ref bool Cancel); public delegate void Completedelegate(); class CustomFileCopier { public CustomFileCopier(string Source, string Dest) { this.SourceFilePath = Source; this.DestFilePath = Dest; OnProgressChanged += delegate { }; OnComplete += delegate { }; } public void Copy() { byte[] buffer = new byte[1024 * 1024]; // … Read more
There’s a lock inside GDI+ that prevents two threads from accessing a bitmap at the same time. This is not a blocking kind of lock, it is a “programmer did something wrong, I’ll throw an exception” kind of lock. Your threads are bombing because you are cloning the image (== accessing a bitmap) in all … Read more