通过fileopenpicker获取所选图像的路径Windows Phone 8.1 C＃

Question

I got an image by using FileOpenPicker. I want to save the path of the image in database, so that by using that path I can get that image any other screen,,

Now I simply send my image path to second page. but with the same Path I'm not able to get image.

Here is my code.

  private async void button_Click(object sender, RoutedEventArgs e)
    {

        ImagePath = string.Empty;
        FileOpenPicker filePicker = new FileOpenPicker();
        filePicker.SuggestedStartLocation = PickerLocationId.PicturesLibrary;
        filePicker.ViewMode = PickerViewMode.Thumbnail;


        filePicker.FileTypeFilter.Clear();
        filePicker.FileTypeFilter.Add(".bmp");
        filePicker.FileTypeFilter.Add(".png");
        filePicker.FileTypeFilter.Add(".jpeg");
        filePicker.FileTypeFilter.Add(".jpg");

        filePicker.PickSingleFileAndContinue();
        view.Activated += viewActivated;
    }

    private async void viewActivated(CoreApplicationView sender, IActivatedEventArgs args1)
    {

        FileOpenPickerContinuationEventArgs args = args1 as FileOpenPickerContinuationEventArgs;

        if (args != null)
        {
            if (args.Files.Count == 0) return;

            view.Activated -= viewActivated;
            StorageFile storageFile = args.Files[0];
            var stream = await storageFile.OpenAsync(Windows.Storage.FileAccessMode.Read);


            **//ImagePath is global string. I get the image path here** 


            ImagePath = storageFile.Path;

            var bitmapImage = new Windows.UI.Xaml.Media.Imaging.BitmapImage();
            await bitmapImage.SetSourceAsync(stream);

            var decoder = await Windows.Graphics.Imaging.BitmapDecoder.CreateAsync(stream);

           //image is my image control in Xaml. 
            image.Source = bitmapImage;
        }

    }

    private void image_click(object sender, TappedRoutedEventArgs e)
    {
        this.Frame.Navigate(typeof(detail), ImagePath);
    }

By tapping on Image I move to detail screen. where I have another image control where I wan to show the same image ,,,,getting through path.

My Detail screen code is:

    protected async override void OnNavigatedTo(NavigationEventArgs e)
    {
        var imagePath = e.Parameter as string;
         image2.Source = new BitmapImage(new Uri(imagePath, UriKind.RelativeOrAbsolute));
    }

The above code didn't work.

Then I tried another way,,

        var file = await Windows.Storage.StorageFile.GetFileFromApplicationUriAsync(new Uri(imagePath));

        Stream stream = await file.OpenStreamForReadAsync();
        using (var memStream = new MemoryStream())
        {
            await stream.CopyToAsync(memStream);
            memStream.Position = 0;

            BitmapDecoder decoder = await BitmapDecoder.CreateAsync(memStream.AsRandomAccessStream());

            // create a new stream and encoder for the new image
            InMemoryRandomAccessStream mrAccessStream = new InMemoryRandomAccessStream();
            BitmapEncoder encoder = await BitmapEncoder.CreateForTranscodingAsync(mrAccessStream, decoder);

            // convert the bitmap to a 400px by 600px bitmap
            encoder.BitmapTransform.ScaledHeight = 400;
            encoder.BitmapTransform.ScaledWidth = 600;

            try
            {
                await encoder.FlushAsync();
            }
            catch (Exception ex)
            {
                string s = ex.ToString();
            }

            // render the stream to the screen
            WB = new WriteableBitmap(500, 500);
            WB.SetSource(mrAccessStream);

            image2.Source = WB;

This also didn't work. I think the problem is in path. I got path awkward path like

      "C:\\Data\\Users\\Public\\Pictures\\Saved Pictures\\Image-130872081698409356.jpeg".

Please help me to get rid of this problem.

Answer 1

This is by design and it is a security issue. Imagine what would happen if just knowing the path to a file you could access that file. The security model of store apps would be broken.

Note that is the file picker that provides you with a file that you have access to. You can start from a file picker to get access to a file. You cannot start from a path to get access to a file. A file picker guarantees that the user will be involved and hence aware of what is going on. If you were allowed to start from a path and programmatically access a file that would violate the security rules for app stores.