从 Xamarin 在内部存储上写入文件时权限被拒绝-解网

问：

我正在尝试执行以下操作：

        var photo = await MediaPicker.CapturePhotoAsync();
        string maindir = Path.Combine(Xamarin.Essentials.FileSystem.AppDataDirectory, "Pictures");
        string filename = System.DateTime.Now.ToString("yyyyMMdd_HHmmss") + System.IO.Path.GetExtension(photo.FileName);
        var newFile = Path.Combine(maindir, filename);
        Directory.CreateDirectory(newFile);
        using (var stream = await photo.OpenReadAsync())
        {
            using (var newStream = File.OpenWrite(newFile))
            {
                await stream.CopyToAsync(newStream);
            }
        }

通过使用，我应该在内部存储中获取一个文件夹（顺便说一句，我还提供了外部存储写入权限，但这应该不相关 - 它没有解决问题）。代码的其余部分几乎逐字摘自 Xamarin.Essentials 文档。Xamarin.Essentials.FileSystem.AppDataDirectory

在 File.OpenWrite 的行中，我收到一个，说“访问路径 '/data/user/0/com.companyname.peerpeek/files/Pictures/20231115_154707.jpg' 被拒绝”。UnauthorizedAccessException

从我所读到的一切来看，这不应该发生。那么：这是一个错误还是我在这里遗漏了一些明显的东西？

为了更好地衡量：在模拟的 Pixel 5 （Android 13）上运行它时以及在自己的手机（Android 12）上调试时，我都会遇到此错误。

[编辑]根据要求：这是完整的例外：

System.UnauthorizedAccessException: Access to the path '/data/user/0/com.companyname.peerpeek/files/Pictures/20231115_163542.jpg' is denied.
  at System.IO.FileStream..ctor (System.String path, System.IO.FileMode mode, System.IO.FileAccess access, System.IO.FileShare share, System.Int32 bufferSize, System.Boolean anonymous, System.IO.FileOptions options) [0x000e7] in /Users/builder/jenkins/workspace/archive-mono/2020-02/android/release/mcs/class/corlib/System.IO/FileStream.cs:196 
  at System.IO.FileStream..ctor (System.String path, System.IO.FileMode mode, System.IO.FileAccess access, System.IO.FileShare share) [0x00000] in /Users/builder/jenkins/workspace/archive-mono/2020-02/android/release/mcs/class/corlib/System.IO/FileStream.cs:91 
  at (wrapper remoting-invoke-with-check) System.IO.FileStream..ctor(string,System.IO.FileMode,System.IO.FileAccess,System.IO.FileShare)
  at System.IO.File.OpenWrite (System.String path) [0x00000] in /Users/builder/jenkins/workspace/archive-mono/2020-02/android/release/external/corefx/src/System.IO.FileSystem/src/System/IO/File.cs:271 
  at PeerPeek.MainPage.LoadPhotoAsync (Xamarin.Essentials.FileResult photo) [0x00187] in C:\Users
icksa\source\repos\PeerPeek\PeerPeek\PeerPeek\MainPage.xaml.cs:88

Android 文件 Xamarin 权限

  var photo = await MediaPicker.CapturePhotoAsync();
  string maindir = Path.Combine(Xamarin.Essentials.FileSystem.AppDataDirectory, "Pictures");
  string filename = System.DateTime.Now.ToString("yyyyMMdd_HHmmss") + System.IO.Path.GetExtension(photo.FileName);
  var newFile = Path.Combine(maindir, filename);
  using (var stream = await photo.OpenReadAsync())
  using (var newStream = File.OpenWrite(newFile))
  await stream.CopyToAsync(newStream);

从 Xamarin 在内部存储上写入文件时权限被拒绝

Permission Denied when writing file on internal storage from Xamarin

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