CODEWITHSUNDEEP
c#.netwpfmultithreadingparallel-processing
Ricardo Polo Jaramillo
Ricardo Polo Jaramillo

Reputation: 12318

Update WPF GUi while Parallel.ForEach

I Have a WPF multithread application, and each thread updates some variables of objects binding to the xaml gui.

If I Use a normal thread or a threadpool it works fine. Each object is being updated at real time in the GUI when the object variables is changed by the treads.

I want to use Parallel.ForEach because it stops the execution util all threads are finished. This is important to me for block the interface (because the use should wait), and for can show a finished message. The bad thing is that with Parallel.Foreach is not being updated in real time, only when all threads are finished.

This way works, but It only updates the Gui at the end.

Parallel.ForEach(Computers, new ParallelOptions { MaxDegreeOfParallelism = 1}, computer => { PingTemp(computer); });

This way works, but It doesn't wait to the end of the ThreadPool.

Task.Factory.StartNew(() => Parallel.ForEach<Computer>(Computers, new ParallelOptions { MaxDegreeOfParallelism = 1 }, computer => PingTemp(computer)));

What approach do you recommend when the GUI is updated in realtime and wait the execution of threadpool before continue.

Upvotes: 0

Views: 3101

Answers (1)

TomTom
TomTom

Reputation: 62093

Do NOT do that in the same thread. If you need the user to wait, then use a mechanism where you LOGICALLY stop interaction at the UI (turn if ff, put a transparent label with a working animation on top of the window) and do things outside the loop. The whole UI interaction is blocked as long as your thread blocks.

YOu do NOT get ANY updates in the UI while the UI thread is blocking. So, that already kills what you want. But more important - you really make bad things. ALWAYS keep the UI free.

My old rule is 0.1/1. Everything longer than 0.1 seconds MUST go into a non-ui thread, anything longer than 1 second MUST disable the UI and show a working animation, preferably one that shows progress if feasible by any mreans.

I use a GUI framework that handles that automatically via bound method signatures (telling the UI this method call is async, then the routine is automatically called in a separate thread).

Upvotes: 3

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