Passing event args and sender to the RelayCommand

.net mvvm-light relaycommand
incognito picture incognito · Jun 3, 2010 · Viewed 16.4k times · Source

How do you get event sender when using RelayCommand?

Answer

Henrik Söderlund picture Henrik Söderlund · Jun 3, 2010

This is one of those pain-in-the-%¤# answers where I don't actually answer your question, but instead lecture you about what you should be doing differently. So, sorry about that. Here goes:

If you find yourself in a position where you need to get at the sender object in your viewmodel, then you should probably do something different. By referencing, say, a Button or a ListBox in your viewmodel you have made that viewmodel aware of UI concepts that it should not know anything about. My suggestion is to instead hook up to the event in the code-behind page, find out what you need to know about the sender or what-not, and then execute the viewmodel command programmatically. That is also breaking the MVVM "rules", but IMHO it is a much slighter hack than referencing the sender in your viewmodel.

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