ActualSizeProxy

/// <summary>
/// Allows binding to a container (or other framework element) height or width
///
/// Example:
///     <UserControl.Resources>
///          <utils:ActualSizePropertyProxy Element="{Binding ElementName=SellPanel}"  x:Name="SellPanelSizeProxy"/>
///     </UserControl.Resources>    
///
///     <TextBlock Width="{Binding ElementName=SellPanelSizeProxy, Path=ActualWidthValue}" />
///
/// </summary>
public class ActualSizePropertyProxy : FrameworkElement, INotifyPropertyChanged
{
    public static readonly DependencyProperty ElementProperty = DependencyProperty.Register(
        "Element",
        typeof(FrameworkElement),
        typeof(ActualSizePropertyProxy),
        new PropertyMetadata(null, OnElementPropertyChanged));
    public event PropertyChangedEventHandler PropertyChanged;
    public FrameworkElement Element
    {
        get { return (FrameworkElement)this.GetValue(ElementProperty); }
        set { this.SetValue(ElementProperty, value); }
    }
    public double ActualHeightValue
    {
        get { return this.Element == null ? 0 : this.Element.ActualHeight; }
    }
    public double ActualWidthValue
    {
        get { return this.Element == null ? 0 : this.Element.ActualWidth; }
    }
    private static void OnElementPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        ((ActualSizePropertyProxy)d).OnElementChanged(e);
    }
    private void OnElementChanged(DependencyPropertyChangedEventArgs e)
    {
        var oldElement = (FrameworkElement)e.OldValue;
        var newElement = (FrameworkElement)e.NewValue;
        newElement.SizeChanged += this.ElementSizeChanged;
        if (oldElement != null)
        {
            oldElement.SizeChanged -= this.ElementSizeChanged;
        }
        this.NotifyPropChange();
    }
    private void ElementSizeChanged(object sender, SizeChangedEventArgs e)
    {
        this.NotifyPropChange();
    }
    private void NotifyPropChange()
    {
        if (this.PropertyChanged != null)
        {
            this.PropertyChanged(this, new PropertyChangedEventArgs("ActualWidthValue"));
            this.PropertyChanged(this, new PropertyChangedEventArgs("ActualHeightValue"));
        }
    }
}

DataContextProxy

using System.Windows;
using System.Windows.Data;
 
namespace Utilities
{
    /// <summary>
    /// Allows binding to a viewmodel from within a data/contenttemplate that is bound to something else.
    ///
    /// Example:
    ///     <UserControl.Resources>
    ///         <DataContextProxy x:Key="dataContextProxy" />
    ///     </UserControl.Resources>    
    ///     ...
    ///     <DataTemplate>
    ///         <Button Content="Delete"
    ///                 Command="{Binding Source={StaticResource dataContextProxy}, Path=DataSource.DeleteClass}" 
    ///                 CommandParameter="{Binding}" />
    ///     </DataTemplate>
    ///
    /// </summary>
    public class DataContextProxy : FrameworkElement
    {
        public DataContextProxy()
        {
            this.Loaded += OnLoaded;
        }
        public string BindingPropertyName { get; set; }
        public BindingMode BindingMode { get; set; }
        public static readonly DependencyProperty DataSourceProperty = DependencyProperty.Register("DataSource", typeof(object), typeof(DataContextProxy), null);
        public object DataSource
        {
            get { return GetValue(DataSourceProperty); }
            set { SetValue(DataSourceProperty, value); }
        }
        private void OnLoaded(object sender, RoutedEventArgs e)
        {
            var binding = new Binding();
            if (!string.IsNullOrEmpty(BindingPropertyName))
            {
                binding.Path = new PropertyPath(BindingPropertyName);
            }
            binding.Source = DataContext;
            binding.Mode = BindingMode;
            SetBinding(DataSourceProperty, binding);
            // this.Loaded -= this.OnLoaded;
        }
    }
}