On the Nerd Plus Art blog today, there was a post about creating WPF Resources for arrows, which the author uses frequently. I have a side project that has Back and Forward buttons, so I thought that the Left and Right arrows would work great on those buttons.
I added the LeftArrow
and RightArrow
Geometries to my application's resources, and then used them as the content of the buttons:
<Application x:Class="Notes.App"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
StartupUri="Views/MainWindow.xaml">
<Application.Resources>
<Geometry x:Key="RightArrow">M0,0 L1,0.5 0,1Z</Geometry>
<Geometry x:Key="LeftArrow">M0,0.5 L1,1 1,0Z</Geometry>
</Application.Resources>
</Application>
<Button x:Name="BackButton"
Padding="5,5,5,5"
Command="{x:Static n:Commands.GoBackCommand}">
<Path Data="{StaticResource LeftArrow}" Width="10" Height="8"
Stretch="Fill" Fill="Black"/>
</Button>
<Button x:Name="ForwardButton"
Padding="5,5,5,5"
Command="{x:Static n:Commands.GoForwardCommand}">
<Path Data="{StaticResource RightArrow}" Width="10" Height="8"
Stretch="Fill" Fill="Red" />
</Button>
That worked, except that the arrows were drawn in black regardless of whether the button was enabled or not. So, I created a ValueConverter
to go from a bool
to a Brush
:
class EnabledColorConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter,
CultureInfo culture)
{
bool b = (bool)value;
return b ? Brushes.Black : Brushes.Gray;
}
public object ConvertBack(object value, Type targetType, object parameter,
CultureInfo culture)
{
throw new NotImplementedException();
}
}
(I realize that I should probably use system colors instead of hard coded black and gray, but I just wanted to get this working, first.)
I modified the Fill
property of the Path
to use my converter (which I created within the application's resources):
<Path Data="{StaticResource LeftArrow}" Width="10" Height="8"
Stretch="Fill"
Fill="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType=Button}, Path=IsEnabled, Converter={StaticResource EnabledColorConverter}}"/>
Unfortunately, this doesn't work, and I'm not sure why. When I run it, the arrow isn't drawn at all. I checked the Output window in Visual Studio, and no binding errors were displayed. I also verified that the bool
is the right value in the converter, based on the whether the button should be enabled or not.
If I change the Path
back to a TextBlock
(and bind its Foreground
property in the same manner as Path.Fill
), the text is always drawn in black.
Am I doing something wrong? Why is the Brush
returned by my converter not used to render the Path
in the button?