共享内存操作类(C#源码)

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()
        {
        }
         ~ 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
        }
    }
}

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 );
                }
            }           
        }

    }
}