Regular readers of my blog know that there are some recurring themes: MVVM, maps and behaviors. I am a big fan of using behaviors ever since I learned how to use this rooting trough the sources of MVVMLight. When I saw the BUILD videos I was elated. I saw a great merger of the best things of Windows and Windows Phone 7 styles and I knew I was going to get on board too. Five months later, I found myself being an MVP and on the Microsoft Campus of all places, and got a pretty unpleasant surprise: a lady presenting the new Expression Blend version said there would be no behaviors in Windows 8 Metro Style XAML. I was quite disappointed at the time. I still think it’s is quite an omission, but then again, when it’s not your deadline it’s always easy to criticize others.
And then for some reason, this week, I remembered a single line from a presentation by Laurent Bugnion on the 2012 Microsoft Techdays in The Hague. “You can’t use behaviors but you can use attached dependency properties”. It kept reverbing trough my brain for a few moments.
“Use the Force, Luke” ;-)
And the result is this. It’s crude, it’s clumsy, it has no Blend support, but it works, more or less – I have been able to port my DragFlickBehavior to Windows 8 and it bloody works, too. This blog post will be split in two parts: in this part, I will show how to make a behavior in Windows 8 XAML in general, and in a next one I will specifically show the DragFlickBehavior itself.
First of all, the behavior class itself:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Windows.UI.Xaml;
namespace WinRtBehaviors
{
public abstract class Behavior : DependencyObject
{
private FrameworkElement associatedObject;
public FrameworkElement AssociatedObject
{
get
{
return associatedObject;
}
set
{
if (associatedObject != null)
{
OnDetaching();
}
associatedObject = value;
if (associatedObject != null)
{
OnAttached();
}
}
}
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