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POHow to implement a background worker thread queue
 

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    <p>I'm trying to implement my first application using the MVVM pattern. I've manged to get most things working, but now I'm facing a problem with the following (IMHO pretty common) scenario:</p> <p>Pressing a <code>Button</code> (View) shall invoke a Method (Model). Using a <code>ICommand</code> (ViewModel) this is pretty easy. But what to do if a time consuming operation has to be executed? </p> <p>My current solution required me to implement a <code>WorkQueue</code> class containing <code>WorkQueueItems</code>. The <code>WorkQueue</code> has a Thread associated with it which executes the <code>WorkQueueItem</code>s. Each <code>WorkQueueItem</code> has a <code>Name</code>, a <code>Status</code> and a <code>Progress</code> which is updated during execution. Each <code>Window</code> has its own <code>WorkQueue</code> - visualized as <code>StatusBar</code>.</p> <p><strong>My problem:</strong> How can a ViewModel find the appropriate <code>WorkQueue</code>? Do I have to pass the <code>WorkQueue</code> to each ViewModel I create (this would be really be annoying)? Or are there other mechanism I could use? </p> <p>I'm not really familiar with <code>RoutedCommand</code>s - tough the basic concept seems to go into this direction. What'd love to see is a solution where I can bind a <code>WorkQueueItem</code> to a Command/Event which then bubbles up to the containing <code>Window</code> where it is added to the <code>Window</code>'s <code>WorkQueue</code>.</p> <p>I also considered making <code>WorkQueue</code> a Singleton - but this only works if I only have one <code>Window</code> at a time.</p>
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    1. COWhich version of .Net? You may have access to [`System.Threading.Tasks`](http://msdn.microsoft.com/en-us/library/system.threading.tasks.aspx).
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    2. CO.NET 4.0 or 4.5 no real limitations apply.
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