WPF Listbox selectionchanged MVVM

Question

I have a list box in my WPF application. I know how to use the selectionchanged event. However I am trying to follow the MVVM design. However I am not sure how to do this.

Answer 1

using SelectionChanged with MVVM is quite simple:

An approach could be to bind to the SelectedIndex property of the ListBox and in the property setter in the VM, act accordingly as it would be triggered whenever the property changes.

Example: Here

In this example whenever the selected index changes, the value of that item is increased by one.

the main bit is:

public int SelectedIndex {
  get {
    return _selectedIndex;
  }

  set {
    if (_selectedIndex == value) {
      return;
    }

    // At this point _selectedIndex is the old selected item's index

    _selectedIndex = value;

    // At this point _selectedIndex is the new selected item's index

    RaisePropertyChanged(() => SelectedIndex);
  }
}

xaml would just be:

Items is the collection of items we bind to.