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POWhy to split the tasks not running on UI thread to make WPF app more responsive?
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copied!<p>In <a href="http://blogs.msdn.com/b/csharpfaq/archive/2010/06/01/parallel-programming-in-net-framework-4-getting-started.aspx" rel="nofollow">part1 "Getting Started"</a> of </p> <ul> <li>Alexandra Rusina's series. Parallel Programming in .NET Framework 4 </li> </ul> <p>in order to make WPF UI responsive, it is done by outsourcing the intensive computations out of UI. Eventually, the code was changed to: </p> <pre><code>for (int i = 2; i < 20; i++) { var t = Task.Factory.StartNew(() => { var result = SumRootN(i); this.Dispatcher.BeginInvoke(new Action(() => textBlock1.Text += "root " + i.ToString() + " " + result.ToString() + Environment.NewLine) ,null); }); } </code></pre> <p>Update: <strong>so shifting the intensive computations out of UI thread.</strong> </p> <p>Here are the quotes from <a href="http://blogs.msdn.com/b/csharpfaq/archive/2010/06/01/parallel-programming-in-net-framework-4-getting-started.aspx" rel="nofollow">Part1 article</a> upon coming to this snippet: </p> <ul> <li><em>"To make the UI responsive, I am going to use tasks, which is a new concept introduced by the Task Parallel Library. A task represents an asynchronous operation that is often run on a separate thread"</em> </li> <li><em>"Compile, run… Well, UI is responsive"</em> </li> </ul> <p>And in order to output to WPF UI from those separate task threads (or to avoid InvalidOperationException that says “The calling thread cannot access this object because a different thread owns it.”) the Dispatcher.BeginInvoke() was engaged. </p> <p>Part2 of the same series <a href="http://blogs.msdn.com/b/csharpfaq/archive/2010/06/18/parallel-programming-task-schedulers-and-synchronization-context.aspx" rel="nofollow">"Parallel Programming: Task Schedulers and Synchronization Context"</a> tells about the same snippet of code (after small change of introducing a local iteration variable): </p> <blockquote> <p>"This one requires more thorough refactoring. I can’t run all the tasks on the UI thread, because they perform long-running operations and this will make my UI freeze. Furthermore, it will cancel all parallelization benefits, because there is only one UI thread.</p> <p>What I can do is to split each task into..."</p> </blockquote> <p>Does not <a href="http://blogs.msdn.com/b/csharpfaq/archive/2010/06/01/parallel-programming-in-net-framework-4-getting-started.aspx" rel="nofollow">the part1-article</a> contradict to <a href="http://blogs.msdn.com/b/csharpfaq/archive/2010/06/18/parallel-programming-task-schedulers-and-synchronization-context.aspx" rel="nofollow">the part2-article</a>? </p> <p>What is the need of splitting the tasks that are not running on UI thread into parts? </p> <p>What do I undermisoverstand here? </p>

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