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【CSharp】共享内存操作类

作者:叶帆工作室 / 发布于2013/7/19/ 882

VC++的共享内存操作代码实现起来相对比较容易，但是用C#语言来实现，就有一定难度，由于工作需要，把以前VC开发的共享内存代码要用C#实现，别说，还费了不少周折，毕竟C#操作API函数和地址指针不是那么直接，还好，总算完成了，效果还不错。


	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()
	 {
	 }
	 ~ShareMem()
	 {
	 Close();
	 }

	 /// <summary>
	 /// 初始化共享内存
	 /// </summary>
	 /// <param name="strName">共享内存名称</param>
	 /// <param name="lngSize">共享内存大小</param>
	 /// <returns></returns>
	 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
	 }
	 /// <summary>
	 /// 关闭共享内存
	 /// </summary>
	 public void Close()
	 {
	 if (m_bInit)
	 {
	 UnmapViewOfFile(m_pwData);
	 CloseHandle(m_hSharedMemoryFile);
	 }
	 }

	 /// <summary>
	 /// 读数据
	 /// </summary>
	 /// <param name="bytData">数据</param>
	 /// <param name="lngAddr">起始地址</param>
	 /// <param name="lngSize">个数</param>
	 /// <returns></returns>
	 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
	 }

	 /// <summary>
	 /// 写数据
	 /// </summary>
	 /// <param name="bytData">数据</param>
	 /// <param name="lngAddr">起始地址</param>
	 /// <param name="lngSize">个数</param>
	 /// <returns></returns>
	 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
	 }
	 }
	}
	测试例程：
	using System;
	using System.Collections.Generic;
	using System.ComponentModel;
	using System.Data;
	using System.Drawing;
	using System.Text;
	using System.Windows.Forms;
	using ShareMemLib;

	namespace YFShareMem
	{
	 public partial class frmShareMem : Form
	 {
	 ShareMem MemDB=new ShareMem();
	 public frmShareMem()
	 {
	 InitializeComponent();
	 }

	 private void btnOpen_Click(object sender, EventArgs e)
	 {
	 if (MemDB.Init("YFMemTest", 10240) != 0)
	 {
	 //初始化失败
	 MessageBox.Show("初始化失败");
	 }
	 else
	 {
	 btnOpen.Enabled = false;
	 chkWrite.Enabled = true;
	 tmrTime.Enabled = true;
	 }
	 }

	 private void tmrTime_Tick(object sender, EventArgs e)
	 {
	 byte[] bytData = new byte[16];
	 int intRet = MemDB.Read(ref bytData, 0, 16);
	 lstData.Items.Clear();
	 if (intRet == 0)
	 {
	 for (int i = 0; i < 16; i++)
	 {
	 lstData.Items.Add(bytData[i].ToString());
	 }

	 if (chkWrite.Checked)
	 {
	 bytData[0]++;
	 bytData[1] += 2;
	 if (bytData[0] > 200) bytData[0] = 0;
	 if (bytData[1] > 200) bytData[1] = 0;
	 MemDB.Write(bytData, 0, 16);
	 }
	 }
	 }

	 }
	}

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