C#内存映射教程(代码)

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

namespace ShareMemLib
{
    public class ShareMem
    {
        [DllImport("user32.dll", CharSet = CharSet.Auto)]
        public static extern IntPtr SendMessage(IntPtr hWnd, int Msg, int wParam, IntPtr lParam);

        [DllImport("Kernel32.dll", CharSet = CharSet.Auto)]
        public static extern IntPtr CreateFileMapping(int hFile, IntPtr lpAttributes, uint flProtect, uint dwMaxSizeHi, uint dwMaxSizeLow, string lpName);
        
        [DllImport("Kernel32.dll", CharSet = CharSet.Auto)]
        public static extern IntPtr OpenFileMapping(int dwDesiredAccess,[MarshalAs(UnmanagedType.Bool)] bool bInheritHandle,string lpName);

        [DllImport("Kernel32.dll", CharSet = CharSet.Auto)]
        public static extern IntPtr MapViewOfFile(IntPtr hFileMapping,uint dwDesiredAccess, uint dwFileOffsetHigh, uint dwFileOffsetLow,uint dwNumberOfBytesToMap);

        [DllImport("Kernel32.dll", CharSet = CharSet.Auto)]
        public static extern bool UnmapViewOfFile(IntPtr pvBaseAddress);

        [DllImport("Kernel32.dll", CharSet = CharSet.Auto)]
        public static extern bool CloseHandle(IntPtr handle);

        [DllImport("kernel32", EntryPoint="GetLastError")]
        public static extern int GetLastError ();

        const int ERROR_ALREADY_EXISTS = 183;

        const int FILE_MAP_COPY = 0x0001;
        const int FILE_MAP_WRITE = 0x0002;
        const int FILE_MAP_READ = 0x0004;
        const int FILE_MAP_ALL_ACCESS = 0x0002 | 0x0004;

        const int PAGE_READONLY = 0x02;
        const int PAGE_READWRITE = 0x04;
        const int PAGE_WRITECOPY = 0x08;
        const int PAGE_EXECUTE = 0x10;
        const int PAGE_EXECUTE_READ = 0x20;
        const int PAGE_EXECUTE_READWRITE = 0x40;

        const int SEC_COMMIT = 0x8000000;
        const int SEC_IMAGE = 0x1000000;
        const int SEC_NOCACHE = 0x10000000;
        const int SEC_RESERVE = 0x4000000;

        const int INVALID_HANDLE_VALUE = -1;

        IntPtr m_hSharedMemoryFile = IntPtr.Zero;
        IntPtr m_pwData = IntPtr.Zero;
        bool m_bAlreadyExist = false;
        bool m_bInit = false;
        long m_MemSize=0;

        public ShareMem()
        {
        }