GifImage.Initialize()方法的小改进，该方法从GIF元数据中读取适当的帧定时。

    private void Initialize()
    {
        _gifDecoder = new GifBitmapDecoder(new Uri("pack://application:,,," + this.GifSource), BitmapCreateOptions.PreservePixelFormat, BitmapCacheOption.Default);

        int duration=0;
        _animation = new Int32AnimationUsingKeyFrames();
        _animation.KeyFrames.Add(new DiscreteInt32KeyFrame(0, KeyTime.FromTimeSpan(new TimeSpan(0))));
        foreach (BitmapFrame frame in _gifDecoder.Frames)
        {
            BitmapMetadata btmd = (BitmapMetadata)frame.Metadata;
            duration += (ushort)btmd.GetQuery("/grctlext/Delay");
            _animation.KeyFrames.Add(new DiscreteInt32KeyFrame(_gifDecoder.Frames.IndexOf(frame)+1, KeyTime.FromTimeSpan(new TimeSpan(duration*100000))));
        }            
         _animation.RepeatBehavior = RepeatBehavior.Forever;
        this.Source = _gifDecoder.Frames[0];            
        _isInitialized = true;
    }

我使用这个库:https://github.com/XamlAnimatedGif/WpfAnimatedGif

首先，将库安装到项目中(使用包管理器控制台):

    PM > Install-Package WpfAnimatedGif

然后，使用这个片段到XAML文件:

    <Window x:Class="WpfAnimatedGif.Demo.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:gif="http://wpfanimatedgif.codeplex.com"
        Title="MainWindow" Height="350" Width="525">
        <Grid>
            <Image gif:ImageBehavior.AnimatedSource="Images/animated.gif" />
        ...

希望能有所帮助。

来源:https://github.com/XamlAnimatedGif/WpfAnimatedGif

这是我的动画图像控制版本。您可以使用标准属性Source来指定图像源。我进一步改进了它。我是俄罗斯人，项目是俄罗斯的，所以评论也是俄语。但是无论如何，你应该能够理解没有注释的一切。：）

/// <summary>
/// Control the "Images", which supports animated GIF.
/// </summary>
public class AnimatedImage : Image
{
    #region Public properties

    /// <summary>
    /// Gets / sets the number of the current frame.
    /// </summary>
    public int FrameIndex
    {
        get { return (int) GetValue(FrameIndexProperty); }
        set { SetValue(FrameIndexProperty, value); }
    }

    /// <summary>
    /// Gets / sets the image that will be drawn.
    /// </summary>
    public new ImageSource Source
    {
        get { return (ImageSource) GetValue(SourceProperty); }
        set { SetValue(SourceProperty, value); }
    }

    #endregion

    #region Protected interface

    /// <summary>
    /// Provides derived classes an opportunity to handle changes to the Source property.
    /// </summary>
    protected virtual void OnSourceChanged(DependencyPropertyChangedEventArgs aEventArgs)
    {
        ClearAnimation();

        BitmapImage lBitmapImage = aEventArgs.NewValue as BitmapImage;

        if (lBitmapImage == null)
        {
            ImageSource lImageSource = aEventArgs.NewValue as ImageSource;
            base.Source = lImageSource;
            return;
        }

        if (!IsAnimatedGifImage(lBitmapImage))
        {
            base.Source = lBitmapImage;
            return;
        }

        PrepareAnimation(lBitmapImage);
    }

    #endregion

    #region Private properties

    private Int32Animation Animation { get; set; }
    private GifBitmapDecoder Decoder { get; set; }
    private bool IsAnimationWorking { get; set; }

    #endregion

    #region Private methods

    private void ClearAnimation()
    {
        if (Animation != null)
        {
            BeginAnimation(FrameIndexProperty, null);
        }

        IsAnimationWorking = false;
        Animation = null;
        Decoder = null;
    }

    private void PrepareAnimation(BitmapImage aBitmapImage)
    {
        Debug.Assert(aBitmapImage != null);

        if (aBitmapImage.UriSource != null)
        {
            Decoder = new GifBitmapDecoder(
                aBitmapImage.UriSource,
                BitmapCreateOptions.PreservePixelFormat,
                BitmapCacheOption.Default);
        }
        else
        {
            aBitmapImage.StreamSource.Position = 0;
            Decoder = new GifBitmapDecoder(
                aBitmapImage.StreamSource,
                BitmapCreateOptions.PreservePixelFormat,
                BitmapCacheOption.Default);
        }

        Animation =
            new Int32Animation(
                0,
                Decoder.Frames.Count - 1,
                new Duration(
                    new TimeSpan(
                        0,
                        0,
                        0,
                        Decoder.Frames.Count / 10,
                        (int) ((Decoder.Frames.Count / 10.0 - Decoder.Frames.Count / 10) * 1000))))
                {
                    RepeatBehavior = RepeatBehavior.Forever
                };

        base.Source = Decoder.Frames[0];
        BeginAnimation(FrameIndexProperty, Animation);
        IsAnimationWorking = true;
    }

    private bool IsAnimatedGifImage(BitmapImage aBitmapImage)
    {
        Debug.Assert(aBitmapImage != null);

        bool lResult = false;
        if (aBitmapImage.UriSource != null)
        {
            BitmapDecoder lBitmapDecoder = BitmapDecoder.Create(
                aBitmapImage.UriSource,
                BitmapCreateOptions.PreservePixelFormat,
                BitmapCacheOption.Default);
            lResult = lBitmapDecoder is GifBitmapDecoder;
        }
        else if (aBitmapImage.StreamSource != null)
        {
            try
            {
                long lStreamPosition = aBitmapImage.StreamSource.Position;
                aBitmapImage.StreamSource.Position = 0;
                GifBitmapDecoder lBitmapDecoder =
                    new GifBitmapDecoder(
                        aBitmapImage.StreamSource,
                        BitmapCreateOptions.PreservePixelFormat,
                        BitmapCacheOption.Default);
                lResult = lBitmapDecoder.Frames.Count > 1;

                aBitmapImage.StreamSource.Position = lStreamPosition;
            }
            catch
            {
                lResult = false;
            }
        }

        return lResult;
    }

    private static void ChangingFrameIndex
        (DependencyObject aObject, DependencyPropertyChangedEventArgs aEventArgs)
    {
        AnimatedImage lAnimatedImage = aObject as AnimatedImage;

        if (lAnimatedImage == null || !lAnimatedImage.IsAnimationWorking)
        {
            return;
        }

        int lFrameIndex = (int) aEventArgs.NewValue;
        ((Image) lAnimatedImage).Source = lAnimatedImage.Decoder.Frames[lFrameIndex];
        lAnimatedImage.InvalidateVisual();
    }

    /// <summary>
    /// Handles changes to the Source property.
    /// </summary>
    private static void OnSourceChanged
        (DependencyObject aObject, DependencyPropertyChangedEventArgs aEventArgs)
    {
        ((AnimatedImage) aObject).OnSourceChanged(aEventArgs);
    }

    #endregion

    #region Dependency Properties

    /// <summary>
    /// FrameIndex Dependency Property
    /// </summary>
    public static readonly DependencyProperty FrameIndexProperty =
        DependencyProperty.Register(
            "FrameIndex",
            typeof (int),
            typeof (AnimatedImage),
            new UIPropertyMetadata(0, ChangingFrameIndex));

    /// <summary>
    /// Source Dependency Property
    /// </summary>
    public new static readonly DependencyProperty SourceProperty =
        DependencyProperty.Register(
            "Source",
            typeof (ImageSource),
            typeof (AnimatedImage),
            new FrameworkPropertyMetadata(
                null,
                FrameworkPropertyMetadataOptions.AffectsRender |
                FrameworkPropertyMetadataOptions.AffectsMeasure,
                OnSourceChanged));

    #endregion
}

我发布了一个扩展图像控件和使用Gif解码器的解决方案。gif解码器有一个frames属性。我动画FrameIndex属性。事件ChangingFrameIndex将源属性更改为与FrameIndex对应的帧(在解码器中)。我猜这个动图每秒有10帧。

class GifImage : Image
{
    private bool _isInitialized;
    private GifBitmapDecoder _gifDecoder;
    private Int32Animation _animation;

    public int FrameIndex
    {
        get { return (int)GetValue(FrameIndexProperty); }
        set { SetValue(FrameIndexProperty, value); }
    }

    private void Initialize()
    {
        _gifDecoder = new GifBitmapDecoder(new Uri("pack://application:,,," + this.GifSource), BitmapCreateOptions.PreservePixelFormat, BitmapCacheOption.Default);
        _animation = new Int32Animation(0, _gifDecoder.Frames.Count - 1, new Duration(new TimeSpan(0, 0, 0, _gifDecoder.Frames.Count / 10, (int)((_gifDecoder.Frames.Count / 10.0 - _gifDecoder.Frames.Count / 10) * 1000))));
        _animation.RepeatBehavior = RepeatBehavior.Forever;
        this.Source = _gifDecoder.Frames[0];

        _isInitialized = true;
    }

    static GifImage()
    {
        VisibilityProperty.OverrideMetadata(typeof (GifImage),
            new FrameworkPropertyMetadata(VisibilityPropertyChanged));
    }

    private static void VisibilityPropertyChanged(DependencyObject sender, DependencyPropertyChangedEventArgs e)
    {
        if ((Visibility)e.NewValue == Visibility.Visible)
        {
            ((GifImage)sender).StartAnimation();
        }
        else
        {
            ((GifImage)sender).StopAnimation();
        }
    }

    public static readonly DependencyProperty FrameIndexProperty =
        DependencyProperty.Register("FrameIndex", typeof(int), typeof(GifImage), new UIPropertyMetadata(0, new PropertyChangedCallback(ChangingFrameIndex)));

    static void ChangingFrameIndex(DependencyObject obj, DependencyPropertyChangedEventArgs ev)
    {
        var gifImage = obj as GifImage;
        gifImage.Source = gifImage._gifDecoder.Frames[(int)ev.NewValue];
    }

    /// <summary>
    /// Defines whether the animation starts on it's own
    /// </summary>
    public bool AutoStart
    {
        get { return (bool)GetValue(AutoStartProperty); }
        set { SetValue(AutoStartProperty, value); }
    }

    public static readonly DependencyProperty AutoStartProperty =
        DependencyProperty.Register("AutoStart", typeof(bool), typeof(GifImage), new UIPropertyMetadata(false, AutoStartPropertyChanged));

    private static void AutoStartPropertyChanged(DependencyObject sender, DependencyPropertyChangedEventArgs e)
    {
        if ((bool)e.NewValue)
            (sender as GifImage).StartAnimation();
    }

    public string GifSource
    {
        get { return (string)GetValue(GifSourceProperty); }
        set { SetValue(GifSourceProperty, value); }
    }

    public static readonly DependencyProperty GifSourceProperty =
        DependencyProperty.Register("GifSource", typeof(string), typeof(GifImage), new UIPropertyMetadata(string.Empty, GifSourcePropertyChanged));

    private static void GifSourcePropertyChanged(DependencyObject sender, DependencyPropertyChangedEventArgs e)
    {
        (sender as GifImage).Initialize();
    }

    /// <summary>
    /// Starts the animation
    /// </summary>
    public void StartAnimation()
    {
        if (!_isInitialized)
            this.Initialize();

        BeginAnimation(FrameIndexProperty, _animation);
    }

    /// <summary>
    /// Stops the animation
    /// </summary>
    public void StopAnimation()
    {
        BeginAnimation(FrameIndexProperty, null);
    }
}

使用示例(XAML):

<controls:GifImage x:Name="gifImage" Stretch="None" GifSource="/SomeImage.gif" AutoStart="True" />

添加到主响应，建议使用WpfAnimatedGif，你必须在最后添加以下行，如果你是交换图像与Gif，以确保动画实际执行:

ImageBehavior.SetRepeatBehavior(img, new RepeatBehavior(0));
ImageBehavior.SetRepeatBehavior(img, RepeatBehavior.Forever);

所以你的代码看起来像这样:

var image = new BitmapImage();
image.BeginInit();
image.UriSource = new Uri(fileName);
image.EndInit();
ImageBehavior.SetAnimatedSource(img, image);
ImageBehavior.SetRepeatBehavior(img, new RepeatBehavior(0));
ImageBehavior.SetRepeatBehavior(img, RepeatBehavior.Forever);

它非常简单，如果你使用<MediaElement>:

<MediaElement  Height="113" HorizontalAlignment="Left" Margin="12,12,0,0" 
Name="mediaElement1" VerticalAlignment="Top" Width="198" Source="C:\Users\abc.gif"
LoadedBehavior="Play" Stretch="Fill" SpeedRatio="1" IsMuted="False" />