我想在我的XAML中显示动画gif，例如loading ...，因为我的程序正在进行中。我发现这在WPF中不能轻易完成，因为我加载了我的Gif并且它只显示了第一帧。在WPF中显示动画的最佳方法是什么。
答案 0 :(得分：4)
您可以使用以下代码在WPF应用中加载GIFImage
using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Media.Imaging;
/// <summary>
/// Class to host nornmal and Gif images and plays the animation.
/// To make it work, instead of setting ImageSource, set the AnimationSourcePath property.
/// </summary>
public class GifImage : Image
{
/// <summary>
/// Dependency property to hold value for AnimationSourcePath.
/// </summary>
public static readonly DependencyProperty AnimationSourcePathProperty =
DependencyProperty.Register(
"AnimationSourcePath",
typeof(string),
typeof(GifImage),
new UIPropertyMetadata(String.Empty, AnimationSourcePathPropertyChanged));
/// <summary>
/// Dependency property to hold value of integer animation timeline values for FrameIndex.
/// </summary>
private static readonly DependencyProperty FrameIndexProperty =
DependencyProperty.Register(
"FrameIndex",
typeof(int),
typeof(GifImage),
new UIPropertyMetadata(0, new PropertyChangedCallback(ChangingFrameIndex)));
/// <summary>
/// Dependency property to hold value of integer animation rate which slows down animation speed if value is more than 1.
/// </summary>
private static readonly DependencyProperty FrameRefreshRateProperty =
DependencyProperty.Register(
"FrameRefreshRate",
typeof(int),
typeof(GifImage),
new UIPropertyMetadata(1, AnimationSourcePathPropertyChanged));
/// <summary>
/// Member to hold animation timeline for integer values.
/// </summary>
private Int32Animation anim;
/// <summary>
/// Member to hold flag to indicate if animation is working.
/// </summary>
private bool animationIsWorking = false;
/// <summary>
/// Member to hold Gif Bitmap Decoder.
/// </summary>
private GifBitmapDecoder gf;
/// <summary>
/// Initializes a new instance of the GifImage class.
/// </summary>
public GifImage()
{
}
/// <summary>
/// Initializes a new instance of the GifImage class based on the uri.
/// </summary>
/// <param name="uri">Uri of the image source.</param>
public GifImage(Uri uri)
{
GifImage.SetupAnimationSource(this, uri);
}
/// <summary>
/// Gets or sets a value indicating AnimationSourcePath.
/// </summary>
public string AnimationSourcePath
{
get { return (string)GetValue(AnimationSourcePathProperty); }
set { SetValue(AnimationSourcePathProperty, value); }
}
/// <summary>
/// Gets or sets a value indicating FrameIndex.
/// </summary>
public int FrameIndex
{
get { return (int)GetValue(FrameIndexProperty); }
set { SetValue(FrameIndexProperty, value); }
}
/// <summary>
/// Gets or sets a value for frame refresh rate. A value more than 1 would slow the animation down.
/// </summary>
public int FrameRefreshRate
{
get { return (int)GetValue(FrameRefreshRateProperty); }
set { SetValue(FrameRefreshRateProperty, value); }
}
/// <summary>
/// Method to handle property changed event of AnimationSourcePath property.
/// </summary>
/// <param name="obj">Source image.</param>
/// <param name="ev">Event arguments.</param>
protected static void AnimationSourcePathPropertyChanged(DependencyObject obj, DependencyPropertyChangedEventArgs ev)
{
GifImage ob = obj as GifImage;
ob.BeginAnimation(GifImage.FrameIndexProperty, null);
ob.anim = null;
ob.gf = null;
ob.Source = null;
if (!String.IsNullOrEmpty(ob.AnimationSourcePath) &&
Uri.IsWellFormedUriString(ob.AnimationSourcePath, UriKind.RelativeOrAbsolute))
{
if (((string)ob.AnimationSourcePath).ToLower().EndsWith(".gif"))
{
Uri uri = new Uri(ob.AnimationSourcePath);
GifImage.SetupAnimationSource(ob, uri);
ob.BeginAnimation(GifImage.FrameIndexProperty, ob.anim);
}
else
{
ob.Source = (new ImageSourceConverter()).ConvertFromString(ob.AnimationSourcePath) as ImageSource;
ob.InvalidateVisual();
}
ob.animationIsWorking = true;
}
}
/// <summary>
/// Method to handle property changed event of FrameIndex property.
/// </summary>
/// <param name="obj">Source image.</param>
/// <param name="ev">Event arguments.</param>
protected static void ChangingFrameIndex(DependencyObject obj, DependencyPropertyChangedEventArgs ev)
{
GifImage ob = obj as GifImage;
ob.Source = ob.gf.Frames[ob.FrameIndex];
ob.InvalidateVisual();
}
/// <summary>
/// Method to setup animation source against a Gif Image.
/// </summary>
/// <param name="ob">Gif image.</param>
/// <param name="uri">Uri of the gif image source.</param>
protected static void SetupAnimationSource(GifImage ob, Uri uri)
{
ob.gf = new GifBitmapDecoder(uri, BitmapCreateOptions.PreservePixelFormat, BitmapCacheOption.Default);
double val = (ob.gf.Frames.Count / 15.0) - (ob.gf.Frames.Count / 15);
TimeSpan tmpSpn = new TimeSpan(0, 0, 0, ob.gf.Frames.Count / 15, (int)(val * 1000));
Duration durtn = new Duration(new TimeSpan(tmpSpn.Ticks * ob.FrameRefreshRate));
ob.anim = new Int32Animation(0, ob.gf.Frames.Count - 1, durtn);
ob.anim.RepeatBehavior = RepeatBehavior.Forever;
ob.Source = ob.gf.Frames[0];
}
/// <summary>
/// Method to override the OnRender event of the image.
/// </summary>
/// <param name="dc">Drawing Context of the image.</param>
protected override void OnRender(DrawingContext dc)
{
base.OnRender(dc);
if (!this.animationIsWorking)
{
BeginAnimation(GifImage.FrameIndexProperty, this.anim);
this.animationIsWorking = true;
}
}
}
您使用它的方式如下....
<ns:GifImage AnimationSourcePath="../MyGifImage.gif" />
如果这有助于您，请告诉我。