利用WPF MediaElement去播放视频或者音乐

来源：互联网发布：java dao设计模式编辑：程序博客网时间：2024/06/05 06:11

本文主要是在学习MediaElement的过程中的心得，比如怎么为自定义控件增加绑定属性，怎么为绑定的MediaElement增加Event的响应，PathGeometry的使用，利用StoryBoard对MediaElement移动进行控制。

在xml中添加Style

            <Style x:Key="MediaStyle" TargetType="MediaElement">                <Setter Property="LoadedBehavior" Value="Manual"></Setter>                <EventSetter Event="MouseDown" Handler="ME_MouseDown"></EventSetter>                <EventSetter Event="MediaEnded" Handler="ME_MediaEnded"></EventSetter>            </Style>

添加播放器的移动路径以及相关的story

            <PathGeometry x:Key="PG">                <PathFigure StartPoint="-100,0">                    <LineSegment Point="50,0"></LineSegment>                    <ArcSegment Point="50,100" RotationAngle="91" IsLargeArc="False" SweepDirection="Clockwise" Size="50,50"></ArcSegment>                    <BezierSegment Point1="6,109" Point2="50,170" Point3="60,190"></BezierSegment>                </PathFigure>            </PathGeometry>            <Storyboard x:Key="KeySB" AutoReverse="True" RepeatBehavior="Forever">                <DoubleAnimationUsingPath Storyboard.TargetName="TT" Storyboard.TargetProperty="X" Source="X" PathGeometry="{StaticResource PG}" Duration="0:0:15"></DoubleAnimationUsingPath>                <DoubleAnimationUsingPath Storyboard.TargetName="TT" Storyboard.TargetProperty="Y" Source="Y" PathGeometry="{StaticResource PG}" Duration="0:0:15"></DoubleAnimationUsingPath>            </Storyboard>

添加MediaElement 控件

        <MediaElement Width="100" Height="100" x:Name="ME" Style="{StaticResource MediaStyle}" Margin="-106,0,302,189" RenderTransformOrigin="0.5,0.5" MouseEnter="img_MouseEnter" MouseLeave="img_MouseLeave" Volume="0">            <MediaElement.RenderTransform>                <TransformGroup>                <TranslateTransform x:Name="TT" />                </TransformGroup>            </MediaElement.RenderTransform>        </MediaElement>

添加Trigger

<EventTrigger RoutedEvent="MediaElement.MediaOpened" SourceName="ME">                <BeginStoryboard Storyboard="{StaticResource KeySB}"></BeginStoryboard>            </EventTrigger>

在.cs文件中添加如下代码

    public partial class VideoPlayer : UserControl    {        public static DependencyProperty VideoSourceDP = DependencyProperty.Register("VideoSource", typeof(ObservableCollection<string>), typeof(VideoPlayer),            new PropertyMetadata(new ObservableCollection<string>(), new PropertyChangedCallback(VideoSourceChanged)));        public ObservableCollection<string> VideoSource        {            get { return GetValue(VideoSourceDP) as ObservableCollection<string>; }            set { SetValue(VideoSourceDP, value); }        }        public int BeginIndex { get; set; }        public VideoPlayer()        {            InitializeComponent();        }        #region virtul function        public virtual void VideoSourceChanged(DependencyPropertyChangedEventArgs e)        {            var newSourceFile = e.NewValue as ObservableCollection<string>;            if (newSourceFile == null) return;                        var old = e.OldValue as ObservableCollection<string>;            if(old != null)                old.CollectionChanged -= Items_CollectionChanged;            var newvalue = e.NewValue as ObservableCollection<string>;            if (newvalue != null)                newvalue.CollectionChanged += Items_CollectionChanged;            if (newSourceFile.Count == 0)            {                //ME.Stop();                //ME.Source = null;            }            else            {                if (BeginIndex >= newSourceFile.Count)                    BeginIndex = 0;                ME.Source = new Uri(newSourceFile[BeginIndex]);                ME.Play();            }        }        void Items_CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)        {            if (ME.Source == null)            {                if(VideoSource.Count > 0)                {                    BeginIndex = 0;                    ME.Source = new Uri(VideoSource[BeginIndex]);                    ME.Play();                }            }            else            {                if(VideoSource.Count == 0)                {                    ME.Stop();                    ME.Source = null;                }            }        }        #endregion        #region static dependency property        public static void VideoSourceChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)        {            var obj = d as VideoPlayer;            if (obj == null) return;            obj.VideoSourceChanged(e);        }        #endregion        #region event        bool bPause = false;        private void ME_MouseDown(object sender, MouseButtonEventArgs e)        {            if(sender == ME)            {                if (!bPause)                    ME.Pause();                else                    ME.Play();                bPause = !bPause;            }        }        #endregion        private void ME_MediaEnded(object sender, RoutedEventArgs e)        {            if(sender == ME)            {                BeginIndex++;                if (BeginIndex >= VideoSource.Count)                    BeginIndex = 0;                ME.Source = new Uri(VideoSource[BeginIndex]);            }        }     }

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