WinRT中的文件共享模式

Question

我有兩個進程寫入同一個文件。它是一個日誌文件BTW，訪問與一個已命名的互斥體同步。

如何使StorageFolder.OpenStreamForWriteAsync傳遞FILE_SHARE_READ | FILE_SHARE_WRITE到它可能從kernelbase.dll使用的底層CreateFile2 WinAPI？

Answer 1

這是不可能的。

解決方法 - 使用非託管互操作實現您自己的FileStream類。這很簡單，我的代碼不到4頁。

這裏的進口，你需要爲：

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); } 

您還需要結構/枚舉/ SafeFileHandle，但與進口，這些都容易複製粘貼，例如從CoreFX。