WinRT中的文件共享模式

Question

我有两个进程写入同一个文件。它是一个日志文件BTW，访问与一个已命名的互斥体同步。

如何使StorageFolder.OpenStreamForWriteAsync传递FILE_SHARE_READ | FILE_SHARE_WRITE到它可能从kernelbase.dll使用的底层CreateFile2 WinAPI？

Answer 1

这是不可能的。

解决方法 - 使用非托管互操作实现您自己的FileStream类。这很简单，我的代码不到4页。

这里的进口，你需要为：

static class NativeMethods 
{ 
    const string file121 = "api-ms-win-core-file-l1-2-1.dll"; 
    const string handle110 = "api-ms-win-core-handle-l1-1-0.dll"; 

    [DllImport(file121, CharSet = CharSet.Unicode, SetLastError = true)] 
    public static extern SafeFileHandle CreateFile2([MarshalAs(UnmanagedType.LPWStr)] string filename, 
     FileAccess dwDesiredAccess, FileShare dwShareMode, FileMode dwCreationDisposition, IntPtr pCreateExParams); 

    [DllImport(handle110, SetLastError = true)] 
    [return: MarshalAs(UnmanagedType.Bool)] 
    internal static extern bool CloseHandle(IntPtr handle); 

    [DllImport(file121, SetLastError = true)] 
    [return: MarshalAs(UnmanagedType.Bool)] 
    static extern bool GetFileInformationByHandleEx(SafeFileHandle handle, FILE_INFO_BY_HANDLE_CLASS FileInformationClass, out FILE_STANDARD_INFO lpFileInformation, int dwBufferSize); 

    internal static FILE_STANDARD_INFO GetFileStandardInfo(SafeFileHandle handle) 
    { 
     FILE_STANDARD_INFO fsi; 
     if(!GetFileInformationByHandleEx(handle, FILE_INFO_BY_HANDLE_CLASS.FileStandardInfo, out fsi, Marshal.SizeOf<FILE_STANDARD_INFO>())) 
      throw new COMException("GetFileInformationByHandleEx failed.", Marshal.GetHRForLastWin32Error()); 
     return fsi; 
    } 

    [DllImport(file121, SetLastError = true)] 
    [return: MarshalAs(UnmanagedType.Bool)] 
    internal static extern bool SetFilePointerEx(SafeFileHandle handle, long liDistanceToMove, out long lpNewFilePointer, SeekOrigin dwMoveMethod); 

    [DllImport(file121, SetLastError = true)] 
    [return: MarshalAs(UnmanagedType.Bool)] 
    internal static extern bool SetFilePointerEx(SafeFileHandle handle, long liDistanceToMove, IntPtr lpNewFilePointer, SeekOrigin dwMoveMethod); 

    [DllImport(file121, SetLastError = true)] 
    [return: MarshalAs(UnmanagedType.Bool)] 
    internal static extern bool FlushFileBuffers(SafeFileHandle handle); 

    [DllImport(file121, SetLastError = true)] 
    [return: MarshalAs(UnmanagedType.Bool)] 
    internal static extern unsafe bool ReadFile(SafeFileHandle hFile, byte* lpBuffer, uint nNumberOfBytesToRead, out uint lpNumberOfBytesRead, IntPtr lpOverlapped); 

    [DllImport(file121, SetLastError = true)] 
    [return: MarshalAs(UnmanagedType.Bool)] 
    internal static extern unsafe bool SetEndOfFile(SafeFileHandle hFile); 

    [ DllImport(file121, SetLastError = true)] 
    [return: MarshalAs(UnmanagedType.Bool)] 
    internal static extern unsafe bool WriteFile(SafeFileHandle hFile, byte* lpBuffer, uint nNumberOfBytesToWrite, out uint lpNumberOfBytesWritten, IntPtr lpOverlapped); } 

您还需要结构/枚举/ SafeFileHandle，但与进口，这些都容易复制粘贴，例如从CoreFX。