使用转换器将颜色绑定到布尔值不会更新

Question

I have a WPF project.

I want to have a brush of a border depending on a bool value of my viewmodel. I wrote a binding to a bool property, which gets updated, and have a special converter from bool to some brush. everything gets call right, but the color does not appear.

I've made a sample application to show the issue:

  <StackPanel>
    <Border BorderThickness="3" BorderBrush="{Binding ElementName=OnOffSwitch, Path=IsChecked, Converter={StaticResource BoolToGreen}, Mode=OneWay}">
        <TextBlock >
            <Run Text="The option is " />
            <Run Text="{Binding ElementName=OnOffSwitch, Path=IsChecked, Mode=OneWay}" />
            <Run Text=" Color should be " />
            <Run Text="{Binding  ElementName=OnOffSwitch, Path=IsChecked, Mode=OneWay, Converter={StaticResource BoolToGreen}}" />
        </TextBlock>
    </Border>
    <CheckBox x:Name="OnOffSwitch" Content="Green" IsChecked="{Binding OnOff}" />
</StackPanel>

My converter looks like this:

[ValueConversion(typeof(bool), typeof(Brush))]
public class BoolToGreenColorConverter : IValueConverter
{
    #region IValueConverter Members

    public object Convert(object value, Type targetType, object parameter,
        System.Globalization.CultureInfo culture)
    {
        return (bool)value ? System.Windows.Media.Colors.Green : System.Windows.Media.Colors.Red;
    }
    //...
}

This is how it looks like in running application:

I also tried other colors, like text block background. It's also not working. Where did I miss something?

Answer 1

Your converter should return System.Windows.Media.Brushes.Green instead of Colors.Green :

public object Convert(object value, Type targetType, object parameter,
    System.Globalization.CultureInfo culture)
{
    return (bool)value ? System.Windows.Media.Brushes.Green : System.Windows.Media.Brushes.Red;
}

The BorderBrush can only be set to a Brush and not to a Color .