How do use MultiBinding for the attached property?

Question

I want to place a Button inside the Canvas and I need to bind the Button "Canvas.Top" Attached property to its own Width property and Height property. How I should build XAML statements?

<Canvas>
  <Button>
    ...
    ...
  </Button>
</Canvas>

Answer 1

I made a sample for your question based on my understanding, if I misunderstand, please point out.
XAML:

  <Window.Resources>  
        <local:ValueConverter x:Key="addValue"></local:ValueConverter>  
    </Window.Resources>  
    <Canvas>  
        <Button Name="btn" Height="20" Width="200">  
            <Canvas.Top>  
                <MultiBinding Converter="{StaticResource addValue}">  
                    <Binding ElementName="btn" Path="Width"/>  
                    <Binding ElementName="btn" Path="Height"/>  
                </MultiBinding>  
            </Canvas.Top>  
        </Button>  
    </Canvas>  

C#:

 public class ValueConverter : IMultiValueConverter  
    {  
        public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)  
        {  
            if (values == null || values.Length == 0)  
                throw new ArgumentNullException("values can not be null");  
            double addedValue = 0.0;  
            foreach(var item in values)  
            {  
                addedValue += System.Convert.ToDouble(item);  
            }  
            return addedValue;  
        }  
  
        public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)  
        {  
            return null;  
        }  
    }  

---

If the response is helpful, please click "Accept Answer" and upvote it.
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.