c# filepicker 限制为 4 个选择 Windows Phone 8.1

Question

有人问过类似的问题here，但我也想知道是否有办法将此 filePicker 限制为 4 个图像，还是我必须自己实现这个？

谢谢

Answer 1

它不是很漂亮，但现在可以用了。我已经声明了两个类型为 ObservableCollection 的全局变量，名为 myimageList 和 alt-myImageList。我刚刚检查了这些集合的大小并从这里开始。

这是代码：

        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;

            foreach (var item in args.Files)
            {
                // instead of item args.Files[0];
                StorageFile storageFile = item;
                var stream = await storageFile.OpenAsync(FileAccessMode.Read);
                var bitmapImage = new BitmapImage();
                await bitmapImage.SetSourceAsync(stream);

                var wbImage = new WriteableBitmap(bitmapImage.PixelWidth, bitmapImage.PixelHeight);
                wbImage.SetSource(stream);

                //var decoder = await Windows.Graphics.Imaging.BitmapDecoder.CreateAsync(stream);
                //bitmapImage.UriSource = new Uri(item.Path, UriKind.Absolute);

                if (myImageList.Count < 4)
                {
                    myImageList.Add(bitmapImage);
                    alt_myImageList.Add(item);
                    ErrorMessage.Text = "";
                }
                else
                {
                    ErrorMessage.Text = "Please pick not more than 4 pictures";
                }
           }
       }

c# filepicker 限制为 4 个选择 Windows Phone 8.1

c# filepicker limit to 4 picks Windows Phone 8.1

c#

winrt-xaml

windows-phone-8.1