File Pickers กับ Save Dialog / Open Dialog บน Windows Store Apps (C#)

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices.WindowsRuntime;
using Windows.Foundation;
using Windows.Foundation.Collections;
using Windows.Storage;
using Windows.Storage.AccessCache;
using Windows.Storage.Pickers;
using Windows.Storage.Provider;
using Windows.Storage.Streams;
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;


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

        protected override void OnNavigatedTo(NavigationEventArgs e)
        {
        }

        private async void SaveAFile_Click(object sender, RoutedEventArgs e)
        {
            FileSavePicker saver = new FileSavePicker();
            saver.SuggestedStartLocation = PickerLocationId.Desktop;
            saver.FileTypeChoices.Add("Text File", new List<string>() { ".txt" });
            saver.SuggestedFileName = "text-name";
            StorageFile file = await saver.PickSaveFileAsync();

            if (file != null)
            {
                CachedFileManager.DeferUpdates(file);
                await FileIO.WriteTextAsync(file, this.txtName.Text);
                FileUpdateStatus status = await CachedFileManager.CompleteUpdatesAsync(file);
            }
        }

    }
}

            FileOpenPicker picker = new FileOpenPicker();
            picker.FileTypeFilter.Add(".png");
            picker.FileTypeFilter.Add(".jpg");
            picker.FileTypeFilter.Add(".gif");
            picker.FileTypeFilter.Add(".bmp");
            picker.SuggestedStartLocation = PickerLocationId.Desktop;
            picker.ViewMode = PickerViewMode.Thumbnail;
            StorageFile file = await picker.PickSingleFileAsync();

            if (file != null)
            {
                using (IRandomAccessStream fileStream = await file.OpenAsync(Windows.Storage.FileAccessMode.Read))
                {
                    BitmapImage bitmapImage = new BitmapImage();

                    await bitmapImage.SetSourceAsync(fileStream);
                    this.imgView.Source = bitmapImage;
                }
            }

<Page
    x:Class="WindowsStoreApps.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:WindowsStoreApps"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d">

    <Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
        <Image x:Name="imgView" Margin="37,29,1147,587"/>
        <Button x:Name="SelectFile" Width="140" Height="54" Content="Select File" Click="SelectFile_Click" Margin="39,212,0,502" />
    </Grid>

</Page>