C#中CreateFileMapping、MapViewOfFile怎么用？
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
[解决办法]
直接改为socket吧。
[解决办法]
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；
[解决办法]
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;
}
[解决办法]
- C# code
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 } }}