Windows Store Apps and Play Media / Sound / Slider Control (C# )

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using Windows.Devices.Geolocation;
using Windows.Foundation;
using Windows.Foundation.Collections;
using Windows.UI.Core;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Controls.Primitives;
using Windows.UI.Xaml.Data;
using Windows.UI.Xaml.Input;
using Windows.UI.Xaml.Media;
using Windows.UI.Xaml.Navigation;

using Windows.Media.PlayTo;
using Windows.Storage;
using Windows.Storage.Pickers;
using Windows.Storage.Streams; 

// The Blank Page item template is documented at http://go.microsoft.com/fwlink/?LinkId=234238

namespace WindowsStoreApps
{
    /// <summary>
    /// An empty page that can be used on its own or navigated to within a Frame.
    /// </summary>
    /// 
    public sealed partial class MainPage : Page
    {

        PlayToManager playToManager = null;
        CoreDispatcher dispatcher = null;
        DispatcherTimer ticks;

        public MainPage()
        {
            this.InitializeComponent();
        }

        protected override void OnNavigatedTo(NavigationEventArgs e)
        {
            dispatcher = Window.Current.CoreWindow.Dispatcher;
            playToManager = PlayToManager.GetForCurrentView();
            playToManager.SourceRequested += playToManager_SourceRequested;
        }


        private void playToManager_SourceRequested(PlayToManager sender, PlayToSourceRequestedEventArgs args)
        {
            var deferral = args.SourceRequest.GetDeferral();
            var handler = dispatcher.RunAsync(CoreDispatcherPriority.Normal, () =>
            {
                args.SourceRequest.SetSource(videosource.PlayToSource);
                deferral.Complete();
            });

        }

        async private void open_Click(object sender, RoutedEventArgs e)
        {
            seek.Value = 0;

            FileOpenPicker filepicker = new FileOpenPicker();
            filepicker.SuggestedStartLocation = PickerLocationId.VideosLibrary;
            filepicker.FileTypeFilter.Add(".mp4");
            filepicker.FileTypeFilter.Add(".wmv");
            filepicker.FileTypeFilter.Add(".mp3");
            filepicker.FileTypeFilter.Add(".flv");
            filepicker.ViewMode = PickerViewMode.Thumbnail;

            StorageFile localVideo = await filepicker.PickSingleFileAsync();
            if (localVideo != null)
            {
                var stream = await localVideo.OpenAsync(FileAccessMode.Read);
                videosource.SetSource(stream, localVideo.ContentType);
            }

        }

        private void videosource_MediaOpened(object sender, RoutedEventArgs e)
        {
            seek.Maximum = videosource.NaturalDuration.TimeSpan.TotalMilliseconds;
            ticks.Interval = TimeSpan.FromMilliseconds(1);
            ticks.Tick += ticks_Tick;
            ticks.Start();
        }

        void ticks_Tick(object sender, object e)
        {
            seek.Value = videosource.Position.TotalMilliseconds;
        }

        private void Play_Click(object sender, RoutedEventArgs e)
        {
            videosource.Play();

        }

        private void pause_Click(object sender, RoutedEventArgs e)
        {
            videosource.Pause();
        }

        private void seek_ValueChanged(object sender, RangeBaseValueChangedEventArgs e)
        {
            int slidervalue = (int)seek.Value;
            TimeSpan ts = new TimeSpan(0, 0, 0, 0, slidervalue);
            videosource.Position = ts;
        }


    }
}