c# - Windows UWP C# 删除文件夹

Question

当我尝试删除文件夹时出现以下错误:

Exception thrown: 'System.UnauthorizedAccessException' in mscorlib.ni.dll

Additional information: Access is denied. (Exception from HRESULT: 0x80070005 (E_ACCESSDENIED))

整个代码块在这里:

StorageFolder folder;

            try

            {

                folder = await ApplicationData.Current.LocalFolder.GetFolderAsync("images");
                await folder.DeleteAsync();

                StorageFolder new_images = await ApplicationData.Current.LocalFolder.CreateFolderAsync("images", CreationCollisionOption.ReplaceExisting);

            }

            catch (FileNotFoundException ex)

            {

                StorageFolder new_images = await ApplicationData.Current.LocalFolder.CreateFolderAsync("images", CreationCollisionOption.ReplaceExisting);

            }

错误发生在这一行:

await folder.DeleteAsync();

我猜当我像这样从图像文件夹中添加一堆图像时会出现问题:

tmp.Source = new BitmapImage(new Uri("ms-appdata:///local/images/image_" + ring.Name + ".jpg", UriKind.Absolute));

也可能是我保存图片的时候:

try {
                StorageFile file = await image_folder.CreateFileAsync("image_" + id + ".jpg", CreationCollisionOption.ReplaceExisting);
                await FileIO.WriteBytesAsync(file, responseBytes);
            } catch (System.Exception)
            {

            }

如果问题是因为它正在读取它而我尝试删除该文件夹，我该如何让它工作，老实说我不知道​​该怎么做。

Answer 1

Exception thrown: 'System.UnauthorizedAccessException' in mscorlib.ni.dll

我注意到您正在尝试使用 FileIO.WriteBytesAsync() 方法保存图像，但我看不到您如何将图像文件加载到 Byte 数组。最可能的原因是“打开它加载图像数据后忘记处理流”

这是我加载图像并保存到 LocalFolder 的方式:

private async Task<byte[]> ConvertImagetoByte(StorageFile image)
{
            IRandomAccessStream fileStream = await image.OpenAsync(FileAccessMode.Read);
            var reader = new Windows.Storage.Streams.DataReader(fileStream.GetInputStreamAt(0));
            await reader.LoadAsync((uint)fileStream.Size);

            byte[] pixels = new byte[fileStream.Size];

            reader.ReadBytes(pixels);

            return pixels;

}

private async void btnSave_Click(object sender, RoutedEventArgs e)
{
            try
            {
                var uri = new Uri("ms-appx:///images/image.jpg");
                var img = await StorageFile.GetFileFromApplicationUriAsync(uri);
                byte[] responseBytes = await ConvertImagetoByte(img);

                var image_folder = await ApplicationData.Current.LocalFolder.CreateFolderAsync("images", CreationCollisionOption.OpenIfExists);

                StorageFile file = await image_folder.CreateFileAsync("image_test.jpg", CreationCollisionOption.ReplaceExisting);
                await FileIO.WriteBytesAsync(file, responseBytes);

                tmp.Source = new BitmapImage(new Uri("ms-appdata:///local/images/image_test.jpg", UriKind.Absolute));
            }
            catch (Exception ex)
            {
                Debug.WriteLine(ex.Message);
            }
}