Doing Drag/Drop without code behind - winrt-xaml

Question

How can I perform drag and drop operations without adding code to the code-behind file?
Can I do this with Attached Properties?
If so, then how?
At first thought, I would think that I could create an attached property and bind it to whatever drag item's property that's associated to dragging. When the state of that property changes, my attached property's valueChanged method handler would then execute the drag logic that is currently located in my code-behind file.
However, I have not identified such a property for drag status.
NOTE:
I am not using Prism because I am implementing a Windows Phone 8.1 app.
Thus, at this time Prism is not supported.

Answer 1

The following answer relates to the overall pattern of managing events of a UIElement with no code-behind.
Summary:
We can access a control that is using an attached property and within that attached property's metadata object, we can call an event handler when the value of the attached property changes.
The value of the attached property is set to "true" in our XAML file. This will immediately trigger the attached property's metadata object to update state and invoke a method handler for the change in value.
This example demonstrates two controls that will change color during their mouse enter event:
XAML code:
<Window x:Class="Temp.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:behaviors="clr-namespace:Temp.Behaviors"
Title="MainWindow" Height="350" Width="525">
<Canvas>
<Ellipse Width="50" Height="50" Fill="Gray" Canvas.Top="0"
behaviors:AttachedProperties.ActivateOnMouseEnter="True" />
<Ellipse Width="50" Height="50" Fill="Gray" Canvas.Left="200"
behaviors:AttachedProperties.ActivateOnMouseEnter="True" />
</Canvas>
</Window>
Attached property code:
using System.Windows;
using System.Windows.Media;
using System.Windows.Shapes;
namespace Temp.Behaviors
{
public class AttachedProperties : DependencyObject
{
public static readonly DependencyProperty ActivateOnMouseEnterProperty =
DependencyProperty.RegisterAttached("ActivateOnMouseEnter", typeof(bool), typeof(AttachedProperties), new PropertyMetadata(false, ActivateOnMouseEnter_ValueChanged));
private static void ActivateOnMouseEnter_ValueChanged(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs e)
{
Ellipse element = dependencyObject as Ellipse;
element.MouseEnter += (se, ev) =>
{
element.Fill = new SolidColorBrush(Colors.Orange);
};
}
public static void SetActivateOnMouseEnter(UIElement element, bool value)
{
element.SetValue(ActivateOnMouseEnterProperty, value);
}
}
}
NOTE:
In this code we are repeatedly subscribing to the mouse enter event without ever unsubscribing (which is bad). However, for simplicity, I leave the logic to manage subscriptions out.