Play a Media File

   
  
<Window x:Class="WpfApplication1.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="WPF" Height="450" Width="300">
    <StackPanel x:Name="Panel">
        <StackPanel.Triggers>
            <EventTrigger RoutedEvent="Button.Click" SourceName="btnPlay">
                <EventTrigger.Actions>
                    <BeginStoryboard Name="ClockStoryboard">
                        <Storyboard x:Name="Storyboard"  SlipBehavior="Slip"
                                    CurrentTimeInvalidated="Storyboard_Changed">
                            <MediaTimeline BeginTime="0" Source="c:a.avi" 
                                 Storyboard.TargetName="meMediaElement"
                                 RepeatBehavior="Forever" />
                        </Storyboard>
                    </BeginStoryboard>
                </EventTrigger.Actions>
            </EventTrigger>
            <EventTrigger RoutedEvent="Button.Click" SourceName="btnPause">
                <EventTrigger.Actions>
                    <PauseStoryboard BeginStoryboardName="ClockStoryboard" />
                </EventTrigger.Actions>
            </EventTrigger>
            <EventTrigger RoutedEvent="Button.Click" SourceName="btnResume">
                <EventTrigger.Actions>
                    <ResumeStoryboard BeginStoryboardName="ClockStoryboard" />
                </EventTrigger.Actions>
            </EventTrigger>
            <EventTrigger RoutedEvent="Button.Click" SourceName="btnStop">
                <EventTrigger.Actions>
                    <StopStoryboard BeginStoryboardName="ClockStoryboard" />
                </EventTrigger.Actions>
            </EventTrigger>
            <EventTrigger RoutedEvent="Slider.PreviewMouseLeftButtonDown" 
                              SourceName="sldPosition" >
                <PauseStoryboard BeginStoryboardName="ClockStoryboard" />
            </EventTrigger>
            <EventTrigger RoutedEvent="Slider.PreviewMouseLeftButtonUp" 
                              SourceName="sldPosition" >
                <ResumeStoryboard BeginStoryboardName="ClockStoryboard" />
            </EventTrigger>
        </StackPanel.Triggers>

        <MediaElement Name="meMediaElement" HorizontalAlignment="Center"
                      Margin="5" MinHeight="300" Stretch="Fill"
                      MediaOpened="MediaOpened" />
        <Button Content="_Play" Name="btnPlay" />
        <Button Content="P_ause" Name="btnPause" />
        <Button Content="_Resume" Name="btnResume" />
        <Button Content="_Stop" Name="btnStop" />
        <Slider HorizontalAlignment="Center" Margin="5" 
                Name="sldPosition" Width="250"
                ValueChanged="sldPosition_ValueChanged">
        </Slider>
        <TextBlock Text="Volume:"/>
        <Slider Minimum="0" Maximum="1" TickFrequency="0.1" TickPlacement="TopLeft" Value="{Binding ElementName=meMediaElement, Path=Volume, Mode=TwoWay}" />
        <TextBlock Text="Balance:"/>
        <Slider Minimum="-1" Maximum="1" TickFrequency="0.2" TickPlacement="TopLeft" Value="{Binding ElementName=meMediaElement, Path=Balance, Mode=TwoWay}" />
    </StackPanel>
</Window>
//File:Window.xaml.cs

using System;
using System.Windows;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;

namespace WpfApplication1
{
    public partial class Window1 : Window
    {
        bool ignoreValueChanged = false;

        public Window1()
        {
            InitializeComponent();
        }
        private void MediaOpened(object sender, EventArgs e)
        {
            sldPosition.Maximum = meMediaElement.NaturalDuration.TimeSpan.TotalMilliseconds;
        }
        private void Storyboard_Changed(object sender, EventArgs e)
        {
            ClockGroup clockGroup = sender as ClockGroup;
            MediaClock mediaClock = clockGroup.Children[0] as MediaClock;
            if (mediaClock.CurrentProgress.HasValue){
                ignoreValueChanged = true;
                sldPosition.Value = meMediaElement.Position.TotalMilliseconds;
                ignoreValueChanged = false;
            }
        }
        private void sldPosition_ValueChanged(object sender, RoutedPropertyChangedEventArgs<double> e){
            if (ignoreValueChanged)
            {
                return;
            }
            Storyboard.Seek(Panel,TimeSpan.FromMilliseconds(sldPosition.Value),TimeSeekOrigin.BeginTime);
        }
    }
}