c# - 为什么这个 P/Invoke 签名不起作用？

Question

我试图从 WinApi 函数编码(marshal) C# 代码.. 但我明白.. 为什么她不工作!文件路径 - 正确，句柄已被使用。 谁能帮帮我？

using System;
using System.Collections.Generic;
using System.Runtime.InteropServices;
using System.Linq;
using System.Text;

namespace ChangeFileTime
{

    class Program
    {

        [DllImport("kernel32.dll", SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        public static extern bool SetFileTime(IntPtr hFile, ref long lpCreationTime,
                                                            ref long lpLastAccessTime, 
                                                            ref long lpLastWriteTime);

        [DllImport("kernel32.dll")]
        public static extern IntPtr CreateFile(string lpFilename,
                                              uint dwDesiredAccess,
                                              uint dwShareMode,
                                              IntPtr SecurityAttributes,
                                              uint dwCreationDisposition,
                                              uint dwFlagsAndAttributes,
                                              IntPtr hTemplateFile);


        [DllImport("kernel32.dll")]
        public static extern bool CloseHandle(IntPtr hObject);

        static void Main(string[] args)
        {
            const uint GENERIC_READ = 0x80000000;
            const uint OPEN_EXISTING = 3;
            const uint FILE_SHARE_WRITE = 0x00000002;
            const uint FILE_ATTRIBUTE_NORMAL = 128;

            IntPtr ptr = CreateFile("C:\\file.txt", GENERIC_READ,
                                                    FILE_SHARE_WRITE,
                                                    IntPtr.Zero,
                                                    OPEN_EXISTING,
                                                    FILE_ATTRIBUTE_NORMAL,
                                                    IntPtr.Zero);

            DateTime creation_time = new DateTime(1990, 12, 14);

            long file_time = creation_time.ToFileTime();
            DateTime time = DateTime.FromFileTime(file_time);

            SetFileTime(ptr, ref file_time, ref file_time, ref file_time);
            int a = 20;
        }
    }
}

我想我弄错了..我尝试编写 C++ 代码，她工作得很好..但为什么在 C# 中不起作用？

Answer 1

来自 MSDN :

The handle must have been created using the CreateFile function with the FILE_WRITE_ATTRIBUTES

这应该有效:

const uint FILE_WRITE_ATTRIBUTES = 0x0100;
IntPtr ptr = CreateFile("C:\\file.txt", FILE_WRITE_ATTRIBUTES, //...