‫استفاده از MVVM زمانیکه امکان Binding وجود ندارد

A 'Binding' cannot be set on the 'Source' property of type 'WebBrowser'.
A 'Binding' can only be set on a DependencyProperty of a DependencyObject.

using System;
using System.Windows;
using System.Windows.Controls;

namespace WebBrowserSample.Behaviors
{
    public static class WebBrowserBehaviors
    {
        public static readonly DependencyProperty BindableSourceProperty =
            DependencyProperty.RegisterAttached("BindableSource",
                            typeof(object),
                            typeof(WebBrowserBehaviors),
                            new UIPropertyMetadata(null, BindableSourcePropertyChanged));

        public static object GetBindableSource(DependencyObject obj)
        {
            return (string)obj.GetValue(BindableSourceProperty);
        }

        public static void SetBindableSource(DependencyObject obj, object value)
        {
            obj.SetValue(BindableSourceProperty, value);
        }

        public static void BindableSourcePropertyChanged(DependencyObject o, DependencyPropertyChangedEventArgs e)
        {
            WebBrowser browser = o as WebBrowser;
            if (browser == null) return;

            Uri uri = null;

            if (e.NewValue is string)
            {
                var uriString = e.NewValue as string;
                uri = string.IsNullOrWhiteSpace(uriString) ? null : new Uri(uriString);
            }
            else if (e.NewValue is Uri)
            {
                uri = e.NewValue as Uri;
            }

            if (uri != null) browser.Source = uri;
        }
    }
}

using System;
using System.ComponentModel;

namespace WebBrowserSample.ViewModels
{
    public class MainWindowViewModel : INotifyPropertyChanged
    {
        Uri _sourceUri;
        public Uri SourceUri
        {
            get { return _sourceUri; }
            set
            {
                _sourceUri = value;
                raisePropertyChanged("SourceUri");
            }
        }

        public MainWindowViewModel()
        {
            SourceUri = new Uri(@"C:\path\arrow.png");
        }

        #region INotifyPropertyChanged Members
        public event PropertyChangedEventHandler PropertyChanged;
        void raisePropertyChanged(string propertyName)
        {
            var handler = PropertyChanged;
            if (handler == null) return;
            handler(this, new PropertyChangedEventArgs(propertyName));
        }
        #endregion
    }
}

<Window x:Class="WebBrowserSample.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:VM="clr-namespace:WebBrowserSample.ViewModels"
        xmlns:B="clr-namespace:WebBrowserSample.Behaviors"
        Title="MainWindow" Height="350" Width="525">
    <Window.Resources>
        <VM:MainWindowViewModel x:Key="vmMainWindowViewModel" />
    </Window.Resources>
    <Grid DataContext="{Binding Source={StaticResource vmMainWindowViewModel}}">
        <WebBrowser B:WebBrowserBehaviors.BindableSource="{Binding SourceUri}" />
    </Grid>
</Window>