Question

How do I bind something like <Color x:Key="SomeColor" /> to a dependency property with Caliburn Micro?

I need to be able to change Color at run-time and have it immediately updated in all things that use it.

Solution:

---

XAML in SomeClassView.xaml

<SomeControl.Resources>
    <SolidColorBrush x:Key="ControlBrush" />
</SomeControl.Resources>

---

C# in SomeClassViewModel.cs

[Export(typeof(MainWindowViewModel))]
public class MainWindowViewModel : PropertyChangedBase
{
    private SolidColorBrush _controlBrush;

    public SolidColorBrush ControlBrush
    {
        get { return _controlBrush; }
        set
        {
            _controlBrush = value;
            NotifyOfPropertyChange(() => ControlBrush);
        }
    }
}

---

The problem was exactly what Charleh said, I just totally forgot that not everything in WPF can be a DependencyProperty.

Answer 1

You can’t usually directly bind a Color object, you need to use a SolidColorBrush (for solid colour), as that’s what most UI objects expect.

e.g.

TextBox.Background expects Brush, of which SolidColorBrush is a subclass of. There are other types of brushes that produce different fills such as LinearGradientBrush

Have a look here:

How can I bind a background color in WPF/XAML?

Can you provide some screenshots of what you expect and the XAML?

Edit:

Ok well what you want is pretty simple to achieve, not really related to Caliburn.Micro at all 🙂

Create your styles as usual, but bind the brushes Color property dynamically using DynamicResource. When you update the colour itself, the resource binding will be evaluated again and the colours will change.

Example XAML:

<Window x:Class="WpfApplication1.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525">
    <Window.Resources>
        <Color x:Key="TestColor" A="255" R="255" G="0" B="0"></Color>
        <Style x:Key="ButtonStyle" TargetType="Button">
            <Setter Property="Background">
                <Setter.Value>
                    <SolidColorBrush Color="{DynamicResource TestColor}"></SolidColorBrush>
                </Setter.Value>
            </Setter>
        </Style>
    </Window.Resources>
    <Grid>
        <StackPanel>
            <Button Click="Button_Click" Style="{StaticResource ButtonStyle}">Red</Button>
            <Button Click="Button_Click_1" Style="{StaticResource ButtonStyle}">Blue</Button>
        </StackPanel>
    </Grid>
</Window>

Code-behind:

namespace WpfApplication1
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

        private void Button_Click(object sender, RoutedEventArgs e)
        {
            Resources["TestColor"] = Color.FromArgb(255, 255, 0, 0);
        }

        private void Button_Click_1(object sender, RoutedEventArgs e)
        {
            Resources["TestColor"] = Color.FromArgb(255, 0, 0, 255);
        }
    }
}