IAsyncOperation question in metro style application

Question

Hi,

in windows8 develop preview version:

 1 void SimpleSample::MainPage::ImageButton_Click(Platform::Object^ sender, Windows::UI::Xaml::RoutedEventArgs^ e)
 2 {
 3 
 4     FileOpenPicker^ open = ref new FileOpenPicker();
 5     // Select display mode
 6     open->ViewMode = PickerViewMode::Thumbnail;
 7     // Start location
 8     open->SuggestedStartLocation = PickerLocationId::Desktop;
 9 
10     open->FileTypeFilter->Append(".jpg");
11     open->FileTypeFilter->Append(".jpeg");
12     open->FileTypeFilter->Append(".png");
13     open->FileTypeFilter->Append(".bmp");
14 
15     // Instantiate a operation and Start.
16     PickSingleFileOperation^ pickOperation = open->PickSingleFileAsync();
17     pickOperation->Completed = ref new AsyncOperationCompletedHandler<StorageFile^>([this] (IAsyncOperation<StorageFile^>^ operation)
18     {
19         StorageFile^ file = operation->GetResults();
20 
21         if(file)
22         {
23             StreamRetrievalOperation^ StreamOperation = file->OpenAsync(FileAccessMode::Read);
24             StreamOperation->Completed = ref new AsyncOperationCompletedHandler<IRandomAccessStream^>([this](IAsyncOperation<IRandomAccessStream
25                 ^>^ operation)
26             {
27                 IRandomAccessStream^ bitmapStream = operation->GetResults();
28                 BitmapImage^ bitmapImage = ref new BitmapImage();
29                 bitmapImage->SetSource(bitmapStream);
30                 ShowImage->Source = bitmapImage;
31             });
32             StreamOperation->Start();
33         }
34     });
35     pickOperation->Start();
36 
37 
38 
39 }

"StreamOperation->Start();" and "pickOperation->Start();" could not used in windows8 consumer preview.

So, how I should do in windows8 consumer preview?

Answer 1

All you need to do is remove the Op->Start(); calls, and then add "AsyncStatus" as your last parameter in the completed handlers.  So for pickOperation->Completed for example it would be " pickOperation->Completed = ref new AsyncOperationCompletedHandler<StorageFile^>([this] (IAsyncOperation<StorageFile^>^ operation, AsyncStatus) "

Answer 2

Hello,

You can follow the updated sample code of "Access and save files using a sample"

http://code.msdn.microsoft.com/windowsapps/File-picker-sample-9f294cba/sourcecode?fileId=43704&pathId=1462329729

void MainPage::Scenario1Button_Click(Object^ sender, Windows::UI::Xaml::RoutedEventArgs^ e) 
{ 
    // Clear previous returned file name, if it exists, between iterations of this scenario 
    Scenario1Reset(); 
 
    if (EnsureUnsnapped()) 
    { 
        FileOpenPicker^ openPicker = ref new FileOpenPicker(); 
        openPicker->ViewMode = PickerViewMode::Thumbnail; 
        openPicker->SuggestedStartLocation = PickerLocationId::PicturesLibrary; 
        openPicker->FileTypeFilter->Append(".jpg"); 
        openPicker->FileTypeFilter->Append(".jpeg"); 
        openPicker->FileTypeFilter->Append(".png"); 
 
        task<StorageFile^>(openPicker->PickSingleFileAsync()).then([this](StorageFile^ file) 
        { 
            if (file) 
            { 
                this->Scenario1FileName->Text = file->Name; 
            } 
            else 
            { 
                this->Scenario1FileName->Text = "File was not returned"; 
            } 
        }); 
    } 
} 

Best regards,
Jesse

---

Jesse Jiang [MSFT]
MSDN Community Support | Feedback to us

Answer 3

23             StreamRetrievalOperation^ StreamOperation = file->OpenAsync(FileAccessMode::Read);
24             StreamOperation->Completed = ref new AsyncOperationCompletedHandler<IRandomAccessStream^>([this](IAsyncOperation<IRandomAccessStream
25                 ^>^ operation)
26             {
27                 IRandomAccessStream^ bitmapStream = operation->GetResults();
28                 BitmapImage^ bitmapImage = ref new BitmapImage();
29                 bitmapImage->SetSource(bitmapStream);
30                 ShowImage->Source = bitmapImage;
31             });

in windows 8 consumer preview:

"BitmapImage^ bitmapImage = ref new BitmapImage();", run into this row, program error.

Answer 4

in windows8 develop preview version:
    m_ras = ref new InMemoryRandomAccessStream();
    auto enc1 = BitmapEncoder::CreateAsync(BitmapEncoder::BmpEncoderId, m_ras);

    try{
        enc1->Completed = ref new AsyncOperationCompletedHandler<BitmapEncoder^>
   ([this](IAsyncOperation<BitmapEncoder^>^ operation, AsyncStatus aaa)
        {
            if(aaa == AsyncStatus::Completed)
   {
                BitmapEncoder^ enc = operation->GetResults();
                Platform::Array<unsigned char>^ p = ref new Platform::Array<unsigned char>(m_pinpix, m_nPixelSize);
                enc->SetPixelData(BitmapPixelFormat::Rgba8, BitmapAlphaMode::Straight,
                m_width, m_height, 96, 96, p);
    auto flushOp = enc->FlushAsync();
    flushOp->Completed = ref new AsyncActionCompletedHandler([this](IAsyncAction ^action, AsyncStatus aaa)
    {
     if(aaa == AsyncStatus::Completed)
     {
      try{
       BitmapImage^ bImg = ref new BitmapImage();
       bImg->SetSource(m_ras);
       this->myImage->Source = bImg;
      }catch(...){
      }
     }
    });
            }

        });
    }catch(...){
    }

how I should do in windows 8 consumer preview?