Can't clear ListBox selection using SelectedItem = null - MVVM

Question

I have the following data template (and a corresponding view model, not shown):

    &l         


        

Answer 1

Forget SelectedItem and SelectedIndex. The answer is SelectedValue, along with IsSynchronizedWithCurrentItem="True".

<ListBox IsSynchronizedWithCurrentItem="True" 
         SelectedValue="{Binding SelectedSnapshotValue}" .../>

Then, when I call ResetSelection() in the view model, SelectedSnapshotValue is set to null,

void ResetSelection()
{
    SelectedSnapshotValue = null;
}

which updates the binding in the data template, using the bound property:

    private SnapshotViewModel selectedSnapshotValue;
    public SnapshotViewModel SelectedSnapshotValue
    {
        get { return selectedSnapshotValue; }
        set
        {
            if (selectedSnapshotValue != value)
            {
                selectedSnapshotValue = value;
                RaisePropertyChanged("SelectedSnapshotValue");
            }
        }
    }

This is the only way I was able to get my listbox to reset the selection.