C#中CreateFileMapping、MapViewOfFile怎么用？

[Jeff20040819]

C++中有这样的代码：
HANDLE hFileMapDest = CreateFileMapping(INVALID_HANDLE_VALUE, NULL, PAGE_READWRITE, 0, sizeof(MCDTYPE1), NULL);
MCDTYPE1* pDest = (MCDTYPE1*)MapViewOfFile(hFileMapDest, FILE_MAP_WRITE, 0, 0, 0);

其中MCDTYPE1是个结构体，请问这样的代码在C#中是怎么用的？需要引用哪些命名空间，有些急，暂时不清楚呢

请大家写详细些，我很久都没有做程序了，很多都忘记了，谢谢大家

[Jeff20040819]

UP

[足球中国]

直接改为socket吧。

[ztenv]

这是windows的API，用于建立文件映射的，和命名空间没有关系，要从系统的dll中导入到C#中，这样才可以调用；

[CsToD]

.Net 4.0支持，今天会发布vs2010beta2（估计美国时间凌晨，所以下午估计可以下载了）

[足球中国]

楼上，真的假的。
这么强大了嘛？？？

[宝_爸]

使用Platform invoke调用API
参考:http://msdn.microsoft.com/en-us/library/aa288468(VS.71).aspx

这两个函数在C#中的声明
[DllImport("kernel32.dll", SetLastError = true, CharSet = CharSet.Auto)]
public static extern IntPtr CreateFileMapping(
IntPtr hFile,
IntPtr lpFileMappingAttributes,
FileMapProtection flProtect,
uint dwMaximumSizeHigh,
uint dwMaximumSizeLow,
[MarshalAs(UnmanagedType.LPTStr)] string lpName);


[DllImport("kernel32.dll", SetLastError = true)]
static extern IntPtr MapViewOfFile(
IntPtr hFileMappingObject,
FileMapAccess dwDesiredAccess,
uint dwFileOffsetHigh,
uint dwFileOffsetLow,
uint dwNumberOfBytesToMap);

[Flags]
public enum FileMapAccess : uint
{
FileMapCopy = 0x0001,
FileMapWrite = 0x0002,
FileMapRead = 0x0004,
FileMapAllAccess = 0x001f,
fileMapExecute = 0x0020,
}

例程:
const UInt32 STANDARD_RIGHTS_REQUIRED = 0x000F0000;
const UInt32 SECTION_QUERY = 0x0001;
const UInt32 SECTION_MAP_WRITE = 0x0002;
const UInt32 SECTION_MAP_READ = 0x0004;
const UInt32 SECTION_MAP_EXECUTE = 0x0008;
const UInt32 SECTION_EXTEND_SIZE = 0x0010;
const UInt32 SECTION_ALL_ACCESS = (STANDARD_RIGHTS_REQUIRED|SECTION_QUERY|
SECTION_MAP_WRITE |
SECTION_MAP_READ |
SECTION_MAP_EXECUTE |
SECTION_EXTEND_SIZE);
const UInt32 FILE_MAP_ALL_ACCESS = SECTION_ALL_ACCESS;
private IntPtr hHandle;
private IntPtr pBuffer;
unsafe public void Attach(string SharedMemoryName, UInt32 NumBytes)
{
if (IntPtr.Zero != hHandle) return;
hHandle = OpenFileMapping(FILE_MAP_ALL_ACCESS, false, SharedMemoryName);
if (IntPtr.Zero == hHandle) return;
pBuffer = MapViewOfFile(hHandle, FILE_MAP_ALL_ACCESS, 0, 0, NumBytes);
}
public void Detach()
{
if (IntPtr.Zero != hHandle)
{
CloseHandle(hHandle); //fair to leak if can't close
hHandle = IntPtr.Zero;
}
pBuffer = IntPtr.Zero;
lBufferSize = 0;
}

[Jeff20040819]

TO:findcaiyzh

在C#中CreateFileMapping MapViewOfFile 不能直接用吧？应该需要引用个什么吧？还是不清楚，亲能不能把把我的C++那两行代码用C#的方式表达出来，谢谢了哈！

[Jeff20040819]

UP

[宝_爸]

还有啥问题？

[Jeff20040819]

UP

[宝_爸]

有这样的声明就可以了
[DllImport("kernel32.dll", SetLastError = true, CharSet = CharSet.Auto)]
kernel32.dll是系统dll。肯定能找得到的。

[宝_爸]

        struct MCDTYPE1
        {
            int a;
            int b;
            int c;

        }

        private void button1_Click(object sender, EventArgs e)
        {
            unsafe
            {
                IntPtr handle = CreateFileMapping(IntPtr.Zero, IntPtr.Zero, FileMapProtection.PageReadWrite, 0, (uint)sizeof(MCDTYPE1), null);

                IntPtr pBuffer = MapViewOfFile(handle, FileMapAccess.FileMapWrite, 0, 0, 0); 
            }
        }

        [DllImport("kernel32.dll", SetLastError = true, CharSet = CharSet.Auto)]
        public static extern IntPtr CreateFileMapping(
            IntPtr hFile,
            IntPtr lpFileMappingAttributes,
            FileMapProtection flProtect,
            uint dwMaximumSizeHigh,
            uint dwMaximumSizeLow,
            [MarshalAs(UnmanagedType.LPTStr)] string lpName);
        
        [Flags]
        public enum FileMapProtection : uint
        {
            PageReadonly = 0x02,
            PageReadWrite = 0x04,
            PageWriteCopy = 0x08,
            PageExecuteRead = 0x20,
            PageExecuteReadWrite = 0x40,
            SectionCommit = 0x8000000,
            SectionImage = 0x1000000,
            SectionNoCache = 0x10000000,
            SectionReserve = 0x4000000,
        }




        [DllImport("kernel32.dll", SetLastError = true)]
        static extern IntPtr MapViewOfFile(
            IntPtr hFileMappingObject,
            FileMapAccess dwDesiredAccess,
            uint dwFileOffsetHigh,
            uint dwFileOffsetLow,
            uint dwNumberOfBytesToMap);

        [Flags]
        public enum FileMapAccess : uint
        {
            FileMapCopy = 0x0001,
            FileMapWrite = 0x0002,
            FileMapRead = 0x0004,
            FileMapAllAccess = 0x001f,
            fileMapExecute = 0x0020,
        } 

[24K純帥]

学习。。

[viki117]

建立内存文件映射，关键的不是函数的作用，这个搜索出来一片，关键是里面各个参数的意义，如何在C#中给这些参数赋值~~~

[viki117]

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

namespace TiiPotDriverForSP.UsbContact
{
    //内存共享类
    internal class Win32Mess
    {
        [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 Win32Mess()
        {
        }
        ~Win32Mess()
        {
            Close();
        }

        /// 
        /// 初始化共享内存
        /// 
        /// 共享内存名称
        /// 共享内存大小
        /// 
        public int Init(string strName, long lngSize)
        {
            if (lngSize <= 0 || lngSize > 0x00800000) lngSize = 0x00800000;
            m_MemSize = lngSize;
            if (strName.Length > 0)
            {
                //创建内存共享体(INVALID_HANDLE_VALUE)
                m_hSharedMemoryFile = CreateFileMapping(INVALID_HANDLE_VALUE, IntPtr.Zero, (uint)PAGE_READWRITE, 0, (uint)lngSize, strName);
                if (m_hSharedMemoryFile == IntPtr.Zero)
                {
                    m_bAlreadyExist = false;
                    m_bInit = false;
                    return 2; //创建共享体失败
                }
                else
                {
                    if (GetLastError() == ERROR_ALREADY_EXISTS) //已经创建
                    {
                        m_bAlreadyExist = true;
                    }
                    else                                         //新创建
                    {
                        m_bAlreadyExist = false;
                    }
                }
                //---------------------------------------
                //创建内存映射
                m_pwData = MapViewOfFile(m_hSharedMemoryFile, FILE_MAP_WRITE, 0, 0, (uint)lngSize);
                if (m_pwData == IntPtr.Zero)
                {
                    m_bInit = false;
                    CloseHandle(m_hSharedMemoryFile);
                    return 3; //创建内存映射失败
                }
                else
                {
                    m_bInit = true;
                    if (m_bAlreadyExist == false)
                    {
                        //初始化
                    }
                }
                //----------------------------------------
            }
            else
            {
                return 1; //参数错误     
            }

            return 0;     //创建成功
        }
        /// 
        /// 关闭共享内存
        /// 
        public void Close()
        {
            if (m_bInit)
            {
                UnmapViewOfFile(m_pwData);
                CloseHandle(m_hSharedMemoryFile);
            }
        }

        /// 
        /// 读数据
        /// 
        /// 数据
        /// 起始地址
        /// 个数
        /// 
        public int Read(ref byte[] bytData, int lngAddr, int lngSize)
        {
            if (lngAddr + lngSize > m_MemSize) return 2; //超出数据区
            if (m_bInit)
            {               
                Marshal.Copy(m_pwData, bytData, lngAddr, lngSize);
            }
            else
            {
                return 1; //共享内存未初始化
            }
            return 0;     //读成功
        }

        /// 
        /// 写数据
        /// 
        /// 数据
        /// 起始地址
        /// 个数
        /// 
        public int Write(byte[] bytData, int lngAddr, int lngSize)
        {
            if (lngAddr + lngSize > m_MemSize) return 2; //超出数据区
            if (m_bInit)
            {
                Marshal.Copy(bytData, lngAddr, m_pwData, lngSize);
            }
            else
            {
                return 1; //共享内存未初始化
            }
            return 0;     //写成功
        }

    }
}