The Progress constructor captures our UI context, So it’s natural to write UI updates: public async void StartProcessingButton_Click(object sender, EventArgs e) One important aspect of this class is that it invokes ProgressChanged (and the Action) in the context in which it was constructed. You can either pass an Action into the constructor or handle the ProgressChanged event. There is one built-in progress reporter: Progress. The caller of the asynchronous method passes in the progress reporter, so it has complete control of how progress reports are handled. Now let’s look at the “receiving” side of progress reports. Async/await will gently nudge you away from OOP and towards functional programming. This is one small step towards a functional mindset. Alternatively, you could make your progress type immutable and make your own copies. This is easy if your progress type is a value type (the compiler makes a copy of it for you). To avoid this problem, you should create a new progress object each time you call Report. It is an error to keep a single “current progress” object, update it, and repeatedly pass it to Report. That second rule can trip people up - it means you can’t modify the progress object after it’s passed to Report. The progress reporter probably hasn’t responded to the progress update by the time your method continues. In other words, you’re “posting” the progress reports to the progress reporter. IProgress.Report is thread-safe, but asynchronous.This means that no progress reports are needed. There are two important things to keep in mind: You can’t get much simpler than that!Īn asynchronous method that wants to report progress just takes an IProgress parameter, with some appropriate type for T. This interface has a single method: void Report(T value). When asynchronous methods report progress, they use an abstraction of the “progress reporter” concept: IProgress. Today, we’ll look at how async methods satisfy a common requirement of background operations: reporting progress. For a limited time, GitHub will match your support.
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