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Editorial Team
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Asked: 2026-05-13T23:57:42+00:00

My WPF application is structured using the MVVM pattern. The ViewModels will communicate asynchronously

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My WPF application is structured using the MVVM pattern. The ViewModels will communicate asynchronously with a server, and when the requested data is returned a callback in the ViewModel is triggered, and it will do something with this data. This will run on a thread which is not the UI Thread. Sometimes these callbacks involve work that needs to be done on the UI thread, so I need the Dispatcher. This might be things such as:

  • Adding data to an ObservableCollection
  • Trigger Prism commands that will set something to be displayed in the GUI
  • Creating WPF objects of some kind.

I try to avoid the latter, but the two first points here I find to be reasonable things for ViewModels to do. So; is it okay to have ViewModels hold the Dispatcher to be able to Invoke commands for the UI thread? Or is this considered bad practice? And why?

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1 Answer

  1. Editorial Team

    Since an ObservableCollection must be updated on the thread it belongs to (assuming a GUI app), and ObservableCollections should be part of the ViewModel, then there’s a clear case for the ViewModel having a Dispatcher.

    I can’t see it being part of the Model.

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