C# 共享内存（转）
以下是一个C#操作内存的一个类，只要将下面的类添加到相应的项目中，该项目就可以对内存进行直接操作！
using System.Runtime.InteropServices; //添加如下命名空间 需要是用 DllImport
public class ShareMemLib
{
[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 ShareMemLib()
{
}
~ShareMemLib()
{
Close();
}
//初始化内存
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
{
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)
{
}
}
}
else
{
return 1;
}
return 0;
}
//关闭共享内存
public void Close()
{
if (m_bInit)
{
UnmapViewOfFile(m_pwData);
CloseHandle(m_hSharedMemoryFile);
}
}
///读数据
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;
}
return 0;
}
//将数据写入共享内存中
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;
}
return 0;
}
｝
调用方法：
声明 ShareMemery.ShareMemLib MemDB = new ShareMemLib(); 为公共的变量
//用下面这句话调用上面类中的初始化共享内存的方法
if (MemDB.Init("YFMemTest", 10240) != 0)
将需要写在内存中的数据：转化成为byte[]
MemDB.Write(bytData, 0, bb.Length); //将数据写入到共享内存中
byte[] bytData = new byte[16];
int intRet = MemDB.Read(ref bytData, 0, 16);
以上方法是读出内存中的16个字节的内容
以上方法在VS2008中经过测试。
