An interesting question from one of the MVVM Light users today:
Is there an MVVM-friendly way to get a DataGrid’s SelectedItems into the ViewModel?
The issue there is as old as the DataGrid (that’s not very old but still): SelectedItem (singular) is a DependencyProperty and can be databound to a property in the ViewModel. SelectedItems (plural) is not a DependencyProperty.
Thankfully the answer is very simple: Use EventToCommand to call a Command in the ViewModel, and pass the SelectedItems collection as parameter. For example, if the command in the ViewModel is declared as follows:
public RelayCommand<IList> SelectionChangedCommand
}and (in the MainViewModel constructor):
SelectionChangedCommand = new RelayCommand<IList>(
if (items == null)
NumberOfItemsSelected = 0;
NumberOfItemsSelected = items.Count;
Then the XAML markup becomes:
I slapped a quick sample and published it here (VS2010, SL4 but the concept works in SL3 and WPF too).
| posted on Wednesday, May 19, 2010 7:17 AM