您发布的代码有几个问题：
您一个接一个地触发文件 I/O 操作，并等待它们完成。由于 UWP 中的文件 I/O 是代理的，这涉及调用另一个进程。由于大部分时间都花在进程之间的通信上，因此您自己的等待会成为瓶颈。在此期间，您的磁盘根本没有活动。
WinRT 文件 I/O API 在性能方面完全是垃圾。你想尽可能地避免它。由于您可以正确访问源路径，因此您应该使用 C# DirectoryInfo 类来枚举文件。然后，不要使用 MoveAsync（因为您不再将源作为 IStorageItem），而是使用 C# 文件 I/O。
通过这些更改，它设法完成我的综合测试用例（40 个文件夹，每个文件夹中有 5 个文件）需要 300 毫秒，而使用您的代码需要 12 秒。那是快 30 倍。如果允许我们使用像 MoveFile 这样的 Win32 API，这可能会变得更快，但不幸的是，目前还没有办法对文件/文件夹选择器选择的文件夹和文件执行此操作。
这是代码。
async Task MoveContentFast(IStorageFolder source, IStorageFolder destination)
{
await Task.Run(() =>
{
MoveContextImpl(new DirectoryInfo(source.Path), destination);
});
}
private void MoveContextImpl(DirectoryInfo sourceFolderInfo, IStorageFolder destination)
{
var tasks = new List<Task>();
var destinationAccess = destination as IStorageFolderHandleAccess;
foreach (var item in sourceFolderInfo.EnumerateFileSystemInfos())
{
if ((item.Attributes & System.IO.FileAttributes.Directory) != 0)
{
tasks.Add(destination.CreateFolderAsync(item.Name, CreationCollisionOption.ReplaceExisting).AsTask().ContinueWith((destinationSubFolder) =>
{
MoveContextImpl((DirectoryInfo)item, destinationSubFolder.Result);
}));
}
else
{
if (destinationAccess == null)
{
// Slower, pre 14393 OS build path
tasks.Add(WindowsRuntimeStorageExtensions.OpenStreamForWriteAsync(destination, item.Name, CreationCollisionOption.ReplaceExisting).ContinueWith((openTask) =>
{
using (var stream = openTask.Result)
{
var sourceBytes = File.ReadAllBytes(item.FullName);
stream.Write(sourceBytes, 0, sourceBytes.Length);
}
File.Delete(item.FullName);
}));
}
else
{
int hr = destinationAccess.Create(item.Name, HANDLE_CREATION_OPTIONS.CREATE_ALWAYS, HANDLE_ACCESS_OPTIONS.WRITE, HANDLE_SHARING_OPTIONS.SHARE_NONE, HANDLE_OPTIONS.NONE, IntPtr.Zero, out SafeFileHandle file);
if (hr < 0)
Marshal.ThrowExceptionForHR(hr);
using (file)
{
using (var stream = new FileStream(file, FileAccess.Write))
{
var sourceBytes = File.ReadAllBytes(item.FullName);
stream.Write(sourceBytes, 0, sourceBytes.Length);
}
}
File.Delete(item.FullName);
}
}
}
Task.WaitAll(tasks.ToArray());
}
[ComImport]
[Guid("DF19938F-5462-48A0-BE65-D2A3271A08D6")]
[InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
internal interface IStorageFolderHandleAccess
{
[PreserveSig]
int Create(
[MarshalAs(UnmanagedType.LPWStr)] string fileName,
HANDLE_CREATION_OPTIONS creationOptions,
HANDLE_ACCESS_OPTIONS accessOptions,
HANDLE_SHARING_OPTIONS sharingOptions,
HANDLE_OPTIONS options,
IntPtr oplockBreakingHandler,
out SafeFileHandle interopHandle); // using Microsoft.Win32.SafeHandles
}
internal enum HANDLE_CREATION_OPTIONS : uint
{
CREATE_NEW = 0x1,
CREATE_ALWAYS = 0x2,
OPEN_EXISTING = 0x3,
OPEN_ALWAYS = 0x4,
TRUNCATE_EXISTING = 0x5,
}
[Flags]
internal enum HANDLE_ACCESS_OPTIONS : uint
{
NONE = 0,
READ_ATTRIBUTES = 0x80,
// 0x120089
READ = SYNCHRONIZE | READ_CONTROL | READ_ATTRIBUTES | FILE_READ_EA | FILE_READ_DATA,
// 0x120116
WRITE = SYNCHRONIZE | READ_CONTROL | FILE_WRITE_ATTRIBUTES | FILE_WRITE_EA | FILE_APPEND_DATA | FILE_WRITE_DATA,
DELETE = 0x10000,
READ_CONTROL = 0x00020000,
SYNCHRONIZE = 0x00100000,
FILE_READ_DATA = 0x00000001,
FILE_WRITE_DATA = 0x00000002,
FILE_APPEND_DATA = 0x00000004,
FILE_READ_EA = 0x00000008,
FILE_WRITE_EA = 0x00000010,
FILE_EXECUTE = 0x00000020,
FILE_WRITE_ATTRIBUTES = 0x00000100,
}
[Flags]
internal enum HANDLE_SHARING_OPTIONS : uint
{
SHARE_NONE = 0,
SHARE_READ = 0x1,
SHARE_WRITE = 0x2,
SHARE_DELETE = 0x4
}
[Flags]
internal enum HANDLE_OPTIONS : uint
{
NONE = 0,
OPEN_REQUIRING_OPLOCK = 0x40000,
DELETE_ON_CLOSE = 0x4000000,
SEQUENTIAL_SCAN = 0x8000000,
RANDOM_ACCESS = 0x10000000,
NO_BUFFERING = 0x20000000,
OVERLAPPED = 0x40000000,
WRITE_THROUGH = 0x80000000
}