Tom Nolane

using MyWindowInDLL;

....
...
 public MainWindow()
        {
            InitializeComponent();
            var wind = new MyWindowInDLL.SuperWindow();
            wind.Show();
        }

public Form1()
        {
            InitializeComponent();
             
            webbrowser.BringToFront(); 
            webbrowser.Visible = true;
            string url = "https://oauth.vk.com/authorize?client_id=" + VK_main.ID_APP + "&display=page&redirect_uri=https://oauth.vk.com/blank.html&scope=" + VK_main.SCOPE + "&response_type=token&v=" + VK_main.VERSION; 
            webbrowser.LoadingFrameComplete += Webbrowser_LoadingFrameComplete; //жду окончания загрузки
            webbrowser.Source = new Uri(url);
        }

        private void Webbrowser_LoadingFrameComplete(object sender, FrameEventArgs e)
        {
            if (!e.IsMainFrame) return;

            if(e.Url.ToString().Contains("https://oauth.vk.com/blank.html#access_token="))
            { 
                int start = e.Url.Fragment.IndexOf("=");
                int end = e.Url.Fragment.IndexOf("&");
                VK_main.TOKEN = e.Url.Fragment.Substring(start+1, end-start-1); // записываю в "глобальную переменную токен
                webbrowser.LoadingFrameComplete -= Webbrowser_LoadingFrameComplete;
                webbrowser.Visible = false;
            }
        }

// image создаю программно, но можно и из x:Name использовать аналогично (без var image = new System.Windows.Controls.Image();)
                        var image = new System.Windows.Controls.Image();
                        BitmapImage bitmap = new BitmapImage();
                        bitmap.BeginInit();
                        bitmap.UriSource = new Uri(path, UriKind.Absolute);
                        bitmap.EndInit();
                        Image.Source = bitmap;

[SerializableAttribute]
[ComVisibleAttribute(true)]
public sealed class Bitmap : Image

<Image Width="90" Height="90" 
       Source="{Binding Path=ImageSource}"
       Margin="0,0,0,5" />

public object ImageSource {
    get {
        BitmapImage image = new BitmapImage();

        try {
            image.BeginInit();
            image.CacheOption = BitmapCacheOption.OnLoad;
            image.CreateOptions = BitmapCreateOptions.IgnoreImageCache;
            image.UriSource = new Uri( FullPath, UriKind.Absolute );
            image.EndInit();
        }
        catch{
            return DependencyProperty.UnsetValue;
        }

        return image;
    }
}

<Image>
    <Image.Source>
        <BitmapImage UriSource="{Binding Path=ImagePath, Converter=...}" />
    </Image.Source>
</Image>

BitmapImage image = new BitmapImage();
image.BeginInit();
image.UriSource = new Uri(value as string);
image.EndInit();

return image;

img.Source = (ImageSource)new ImageSourceConverter().ConvertFromString("/www/image.png");

Assembly assembly = Assembly.LoadFrom("https://мой_сайт.ru/Library2.dll");
                Type type = assembly.GetType("Library2.MainWindow");
                dynamic obj = Activator.CreateInstance(type);
                Window extern= (Window)obj;
                exnter .Show();  
// extern- wpf переделанный в dll

<Page>
 <Page.Resources>
            <Class1 x:Key="blablabla"></Class1 >
        </Page.Resources>
<Grid DataContext="{Binding Source={StaticResource blablabla}}"....
// ваш код xaml после чего у mycontrols ставите атрибуты
</Grid>
 </Page>
</Window>