WP71 MVVMLight EventTrigger not recognised - windows-phone-7

Question

Having followed Laurent's upgrade guide http://www.galasoft.ch/mvvm/installing/mangobeta/ to get from an existing MVVMLight WP7 project to a WP71 project. I have changed the references and namespaces corectly. But the EventTrigger is not recognised in the XAML
xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"
<i:Interaction.Triggers>
<i:EventTrigger EventName="Loaded">
<cmd:EventToCommand
Command="{Binding Mode=OneWay, Path=LoadedCommand}"
PassEventArgsToCommand="True" />
</i:EventTrigger>
</i:Interaction.Triggers>
I get an error on the EventTrigger element.
Has it changed?

Answer 1

I had this exact same problem when I upgrade my application from WP7 to WP7.1(Mango). The problem was the MVVM Light Binaries. You need to upgrade to the WP7.1 Binaries.
Laurent Bugnion ( https://stackoverflow.com/users/12233/lbugnion ) explains how to upgrade the MVVM Light binaries on his website here: http://www.galasoft.ch/mvvm/installing/mangobeta/
These are the essential steps I used to fix my problem:
Download the most recent version from here.
Open and Compile the WP71 project.
Copy the binaries to your MVVM Binary location (in my case C:\Program Files\Laurent Bugnion (GalaSoft)\Mvvm Light Toolkit\Binaries)
Open your project
In the References folder, delete GalaSoft.MvvmLight, GalaSoft.MvvmLight.Extras and System.Windows.Interactivity.
Add the new references from the folder C:\Program Files\Laurent Bugnion (GalaSoft)\Mvvm Light Toolkit\Binaries\WP71.

Answer 2

I had a similar problem after upgrading to Mango. In my case, I had the EventToCommand binding on a MenuItem click, but you seem to have it on some sort of loaded event. You could try using an anonymous delegate in the loaded evcent from the view's code-bhind. Ie:
this.Loaded+=(s,e)=>ViewModel.LoadedCommand.Execute(null);
In my case, I changed from:
<tk:MenuItem Header="Delete Snapshot" >
<i:Interaction.Triggers>
<i:EventTrigger EventName="Click">
<mvvmLight:EventToCommand Command="{Binding DeleteSnapshotCommand, Mode=OneWay}" CommandParameter="{Binding SelectedItem,ElementName=lstSnapshots}" />
</i:EventTrigger>
</i:Interaction.Triggers>
</tk:MenuItem>
to
<tk:MenuItem Header="Delete Snapshot" Command="{Binding DeleteSnapshotCommand, Mode=OneWay}" CommandParameter="{Binding SelectedItem,ElementName=lstSnapshots}" />

Answer 3

I have moved on from this issue, by reverting back to pre-mango dev environment.
Not the solution I wanted, but - onwards and forwards.