How can i change the backround color of a rectange by clicking on a checkbox

Question

Im Using Blend and have the following Problem:

How can i Change the Background Color of a rectangle by clicking on a checkbox? When i go via right click, edit template and then edit a copy i can only edit the current object. In this cas it would be the checkbox. But i want to use the checkbox to edit the style of a rectange object. Is this possible?

Answer 1

you can bind to the IsChecked property and use a ValueConverter

<CheckBox x:Name="cb" />
<Rectangle Fill="{Binding ElementName=cb, Path=IsChecked, Mode=OneWay, Converter={StaticResource CheckedToBackgroundConverter}}" />

the value converter

public class CheckedToBackgroundConverter: IValueConverter
{
  public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
  {
    return value is bool && (bool)value ? Brushes.Blue : Brushes.Red;
  }

  public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
  {
    return DependencyProperty.UnsetValue;
  }
}

hope that helps