Facebook SDK for .NETを使い、アプリから画像をFacebookに投稿させるには：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（4）（5/5 ページ）

    Protected Overrides Sub OnNavigatedTo(e As Navigation.NavigationEventArgs)
        myBmp = CType(e.Parameter, BitmapImage)
        MainImage.Source = myBmp
    End Sub

    Private Async Sub UploadButton_Click(sender As Object, e As RoutedEventArgs) Handles uploadButton.Click
        uploadButton.IsEnabled = False
        If messageTextBox.Text = String.Empty Then
            Dim message As New MessageDialog("コメントを入力してください。")
            Await message.ShowAsync
            uploadButton.IsEnabled = False
            Exit Sub
        Else
            ProgressRing1.IsEnabled = True
            ProgressRing1.IsActive = True
            myFB = New FacebookClient(accessToken)
            AddHandler myFB.PostCompleted, Async Sub(mySender As Object, myArgs As FacebookApiEventArgs)
                                      If myArgs.Cancelled Then
                                    Dim cancellationError = myArgs.Error
                                     ElseIf myArgs.Error Is Nothing = False Then
  　                                       Dim myDialog2 As MessageDialog = New MessageDialog("アップロード失敗")
                                          Await myDialog2.ShowAsync()
      　                                   flag = False
                                       Else
                                          flag = True
                                       End If
                           End Sub
            '　このプログラムの肝、Facebookにコメント付き画像をアップロードする処理。
            Using myStream As IO.Stream = Await myFile.OpenStreamForReadAsync()
                Await myFB.PostTaskAsync("/me/photos", New With {.message = messageTextBox.Text, .file = New FacebookMediaStream() With {.ContentType = "image/jpeg", .FileName = FileName}.SetValue(myStream)})
            End Using
        End If
        If flag = True Then
            ProgressRing1.IsEnabled = False
            ProgressRing1.IsActive = False
            Dim message As New MessageDialog("アップロード成功")
            Await message.ShowAsync
            uploadButton.IsEnabled = True
        Else
            Dim message As New MessageDialog("アップロード失敗")
            Await message.ShowAsync
            uploadButton.IsEnabled = True
            Exit Sub
        End If
    End Sub
End Class