如何将控件的属性与XAML（WPF）中的某些计算绑定？

Question

for example , if I want to draw a square, per side 50 px ,the code like this : <Rectangle Width="50" Height="{Binding Path=Width,RelativeSource={RelativeSource Self}}" Fill="Blue"/> ; but if I want to let the height always equals to half of width , the code is not correct : <Rectangle Width="50" Height="{Binding Path=Width/2,RelativeSource={RelativeSource Self}}" Fill="Blue"/> , so how to do it in XAML ?

Answer 1

Something like this. Code behind:

public class MyConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        return ((double)value)/2;
    }

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

And xaml:

<local:MyConverter x:key="MyConverter"/>



<Rectangle Width="50" Height="{Binding Path=Width,RelativeSource={RelativeSource Self}, Converter={StaticResource MyConverter}}" Fill="Blue"/>