红糖糍粑
我发布了一个解决方案，扩展图像控制和使用GIF解码器。GIF解码器具有帧属性。我把FrameIndex财产。事件ChangingFrameIndex将源属性更改为与FrameIndex(即在解码器中)。我猜GIF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);
}}用法示例(XAML)：<controls:GifImage x:Name="gifImage" Stretch="None" GifSource="/SomeImage.gif" AutoStart="True" />