While trying to figure out how to add a generic mechanism for accelerators on buttons on my Win8 port of Bridge Stenographer I was faced with blank stares when asking about Keyboard Shortcuts
AutomationProperties.AccessKey="Number2" looked like the perfect property to add on my 2 button for instance, but I was disappointed to find out that nothing supported it.
In the end, I needed to have a base class that did some of the handling for my keyboard mapping to the access keys, as I don’t want to write that code over and over again (actually, I don’t want to debug and keep parallel copies up to date, but I digress).
So, what better way than a base class I thought.
So, here’s what I did. I had my keyboard like control based on a UserControl. Why not just change the base class to SpecializedUserControl like this:
public class SpecializedUserControl : UserControl
{
public SpecializedUserControl()
{
}
public void ExtraFunctionality()
{
}
}
Then, I can create a new user control, and base it on this new base class like this:
public sealed partial class MySpecializedUserControlInstance : SpecializedUserControl
{
public MySpecializedUserControlInstance()
{
this.InitializeComponent();
}
}
and declare it in XAML like this:
<local:SpecializedUserControl
x:Class="hoverbug.MySpecializedUserControlInstance"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:repro"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
d:DesignHeight="300"
d:DesignWidth="400">
<Grid>
<Button>Sorry Charlie!</Button>
</Grid>
</local:SpecializedUserControl>
Interestingly, while writing this, I was disappointed to find that everything worked fine, and I wasn’t getting the error I got in my actual code.
Here’s how I instantiated the control on my page:
<local:MySpecializedUserControlInstance DataContext={Binding }" />Not to be beaten (as it really didn’t appear to work in my code), I started porting across bits of my implementation, a feature of which was that I needed a property to attach to controls in my implementation that could hold a function to call when the AccessKey was pressed, so I did it like this in SpecializedUserControl:
public RoutedEventHandler KeyboardAction
{
get { return (RoutedEventHandler)GetValue(KeyboardActionProperty); }
set { SetValue(KeyboardActionProperty, value); }
}
// Using a DependencyProperty as the backing store for KeyboardAction. This enables animation, styling, binding, etc...
public static readonly DependencyProperty KeyboardActionProperty =
DependencyProperty.RegisterAttached("KeyboardAction", typeof(RoutedEventHandler), typeof(SpecializedUserControl),
new PropertyMetadata(null));
Now when I run the same program, I get this error:
Anyone have any idea why adding a declaration of an attached property breaks it in this way?
