Question

I am trying to use library from https://github.com/XamlAnimatedGif/WpfAnimatedGif/ to solve my animation gif using wpf. I wrote some code to bind the image to the Image, but it is not working.

WPF:

<Image gif:ImageBehavior.RepeatBehavior="Forever"
           gif:ImageBehavior.AnimatedSource="{Binding ElementName=WpfAnimation, Path=ImageStatus}"/>

Code Behind:

// Image status property
        public readonly DependencyProperty ImageStatusProperty;
    public ImageSource ImageStatus
    {
        get { return (ImageSource)GetValue(ImageStatusProperty); }
        set { SetValue(ImageStatusProperty, value); }
    }

    public MainWindow()
    {
        InitializeComponent();
        ImageStatus = new BitmapImage(new Uri("Images/anipier_e0.gif", UriKind.Relative));

    }

Error:

System.Windows.Markup.XamlParseException was unhandled
  HResult=-2146233087
  Message='The invocation of the constructor on type 'WpfAnimation.MainWindow' that matches the specified binding constraints threw an exception.' Line number '4' and line position '9'.
  Source=PresentationFramework
InnerException: System.ArgumentNullException
       HResult=-2147467261
       Message=Value cannot be null.

Thank you.

Answer 1

I think something is wrong with your binding : AnimatedSource is binding to an element named “WpfAnimation”. You should bind the AnimatedSource to a property of your DataContext. If WpfAnimation is similar to LayoutRoot, use an expression like this :

<Image gif:ImageBehavior.RepeatBehavior="Forever"
           gif:ImageBehavior.AnimatedSource="{Binding ElementName=WpfAnimation, Path=DataContext.ImageStatus}"/>

Also, check the Debug/Output for binding errors, that the animated gif is a resource, that your Uri is valid, and that a DataContext is associated to your view.

EDIT:

Looks like there is a exception in the view constructor.