Question

How do I bind the ListViews visibility to a calculation? I want the Listviews to be visible ONLY if there are more than one record in the DataContexts Collection (IEnumerable)

Answer 1

You can create a property CollectionAny on a ViewModel, which will call IEnumerable.Any() method. You can return Visibility directly from your ViewModel, but it is not recommended by MVVM pattern. So you are able to use converter, such as BooleanToVisibilityConverter. If you can wrap your collection to a ICollecitionView interface, you can use its IsEmpty property. If it is your choice – you do not need to raise PropertyChanged event.

Here example of binding boolean property to Visibility:

<!-- Inside your resources define the converter instance -->
<BooleanToVisibilityConverter x:Key="B2VConverter">
...

<ListView 
    ...
    Visibility="{Binding Path=CollectionAny, Converter={StaticResource B2VConverter}}" 
    ...
/>