選択した画像と、テクスチャとなる画像を合成して保存するには：2カ月で160本作った還暦開発者が送る10のアプリ開発ノウハウ（7）（4/4 ページ）

‘ 要素の厳密に型指定された読み取り専用のコレクションを表す、IReadOnlyCollection(Of IStorageFile)型の
‘　メンバー変数myPictureFilesを宣言する。
    Private myPictureFiles As IReadOnlyCollection(Of IStorageFile)

    Protected Overrides Async Sub OnNavigatedTo(e As Navigation.NavigationEventArgs)
        RemoveHandler GridView1.Loaded, AddressOf Me.GridView1_Loaded
        Await DataShow()
    End Sub

    Private Async Function DataShow() As Task
        GridView1.Items.Clear()
        Dim myFolder As StorageFolder = Windows.Storage.KnownFolders.PicturesLibrary
        Dim mySubFolder = Await myFolder.CreateFolderAsync("BiltImage", CreationCollisionOption.OpenIfExists)
        myPictureFiles = Await mySubFolder.GetFilesAsync()
        If myPictureFiles.Count = 0 Then
            Dim message As New MessageDialog("画像はありません。戻ってください。")
            Await message.ShowAsync
            Exit Function
        End If
        For Each myPhotoFile In myPictureFiles
            Dim bmp As New BitmapImage
            bmp.SetSource(Await myPhotoFile.OpenSequentialReadAsync)
            Dim myImage As New Image
            myImage.Width = 640
            myImage.Height = 480
            myImage.Source = bmp
            Dim myFileName As New TextBlock
            myFileName.Text = myPhotoFile.Name
            myFileName.FontSize = 20
            myFileName.HorizontalAlignment = Windows.UI.Xaml.HorizontalAlignment.Center
            Dim myStackPanel As New StackPanel
            myStackPanel.Margin = New Thickness(3)
            myStackPanel.Children.Add(myImage)
            myStackPanel.Children.Add(myFileName)
            GridView1.Items.Add(myStackPanel)
        Next
        AddHandler GridView1.Loaded, AddressOf Me.GridView1_Loaded
    End Function

    Private Sub GridView1_Loaded(sender As Object, e As Object)
        Dim _myIndex As Integer = 0
        _myIndex = myPictureFiles.Count - 1
        If _myIndex < 0 Then
            Exit Sub
        Else
            GridView1.Focus(Windows.UI.Xaml.FocusState.Keyboard)
            GridView1.SelectedIndex = _myIndex
            GridView1.ScrollIntoView(GridView1.SelectedItem)
        End If
    End Sub