进程间通信——共享内存

骑猪看日落 2023-01-01 03:47 393阅读 0赞

# 接收端 #

![20201231101301160.png][]

using System;
    using System.Collections.Generic;
    using System.ComponentModel;
    using System.Data;
    using System.Drawing;
    using System.Linq;
    using System.Runtime.InteropServices;
    using System.Text;
    using System.Threading;
    using System.Threading.Tasks;
    using System.Windows.Forms;
    
    namespace WindowsFormsApp1
    {
        public partial class Form1 : Form
        {
            const int INVALID_HANDLE_VALUE = -1;
            const int PAGE_READWRITE = 0x04;
    
            [DllImport("User32.dll")]
            private static extern bool ShowWindowAsync(IntPtr hWnd, int cmdShow);
            [DllImport("User32.dll")]
            private static extern bool SetForegroundWindow(IntPtr hWnd);
    
            //共享内存
            [DllImport("Kernel32.dll", EntryPoint = "CreateFileMapping")]
            private static extern IntPtr CreateFileMapping(IntPtr hFile, //HANDLE hFile,
             UInt32 lpAttributes,//LPSECURITY_ATTRIBUTES lpAttributes,  //0
             UInt32 flProtect,//DWORD flProtect
             UInt32 dwMaximumSizeHigh,//DWORD dwMaximumSizeHigh,
             UInt32 dwMaximumSizeLow,//DWORD dwMaximumSizeLow,
             string lpName//LPCTSTR lpName
             );
    
            [DllImport("Kernel32.dll", EntryPoint = "OpenFileMapping")]
            private static extern IntPtr OpenFileMapping(
             UInt32 dwDesiredAccess,//DWORD dwDesiredAccess,
             int bInheritHandle,//BOOL bInheritHandle,
             string lpName//LPCTSTR lpName
             );
    
            const int FILE_MAP_ALL_ACCESS = 0x0002;
            const int FILE_MAP_WRITE = 0x0002;
    
            [DllImport("Kernel32.dll", EntryPoint = "MapViewOfFile")]
            private static extern IntPtr MapViewOfFile(
             IntPtr hFileMappingObject,//HANDLE hFileMappingObject,
             UInt32 dwDesiredAccess,//DWORD dwDesiredAccess
             UInt32 dwFileOffsetHight,//DWORD dwFileOffsetHigh,
             UInt32 dwFileOffsetLow,//DWORD dwFileOffsetLow,
             UInt32 dwNumberOfBytesToMap//SIZE_T dwNumberOfBytesToMap
             );
    
            [DllImport("Kernel32.dll", EntryPoint = "UnmapViewOfFile")]
            private static extern int UnmapViewOfFile(IntPtr lpBaseAddress);
    
            [DllImport("Kernel32.dll", EntryPoint = "CloseHandle")]
            private static extern int CloseHandle(IntPtr hObject);
    
            private Semaphore m_Write;  //可写的信号
            private Semaphore m_Read;  //可读的信号
            private IntPtr handle;     //文件句柄
            private IntPtr addr;       //共享内存地址
            uint mapLength;            //共享内存长
    
            //线程用来读取数据
            Thread threadRed;
            public Form1()
            {
                InitializeComponent();
                init();
            }
    
    
            ///<summary>/// 初始化共享内存数据 创建一个共享内存
            ///</summary>
            private void init()
            {
                m_Write = new Semaphore(1, 1, "WriteMap");//开始的时候有一个可以写
                m_Read = new Semaphore(0, 1, "ReadMap");//没有数据可读
                mapLength = 1024;
                IntPtr hFile = new IntPtr(INVALID_HANDLE_VALUE);
                handle = CreateFileMapping(hFile, 0, PAGE_READWRITE, 0, mapLength, "shareMemory");
                addr = MapViewOfFile(handle, FILE_MAP_ALL_ACCESS, 0, 0, 0);
    
                threadRed = new Thread(new ThreadStart(ThreadReceive));
                threadRed.Start();
            }
    
            /// <summary>
            /// 线程启动从共享内存中获取数据信息 
            /// </summary>
            private void ThreadReceive()
            {
                while (true)
                {
                    try
                    {
                        //读取共享内存中的数据：
                        //是否有数据写过来
                        m_Read.WaitOne();
                        //IntPtr m_Sender = MapViewOfFile(handle, FILE_MAP_ALL_ACCESS, 0, 0, 0);
                        byte[] byteStr = new byte[100];
                        byteCopy(byteStr, addr);
                        string str = Encoding.Default.GetString(byteStr, 0, byteStr.Length);
                        this.Invoke((MethodInvoker)(delegate ()
                        { textBox1.Text = str.Trim(); })
                            );
                        /调用数据处理方法 处理读取到的数据
                        m_Write.Release();
                    }
                    catch (WaitHandleCannotBeOpenedException)
                    {
                        continue;
                        //Thread.Sleep(0);
                    }
    
                }
    
            }
            //不安全的代码在项目生成的选项中选中允许不安全代码
            static unsafe void byteCopy(byte[] dst, IntPtr src)
            {
                fixed (byte* pDst = dst)
                {
                    byte* pdst = pDst;
                    byte* psrc = (byte*)src;
                    while ((*pdst++ = *psrc++) != '\0')
                        ;
                }
    
            }
    
        }
    }

# 发送端 #

![20201231101404184.png][]

using System;
    using System.Collections.Generic;
    using System.ComponentModel;
    using System.Data;
    using System.Drawing;
    using System.Linq;
    using System.Runtime.InteropServices;
    using System.Text;
    using System.Threading;
    using System.Threading.Tasks;
    using System.Windows.Forms;
    
    namespace WindowsFormsApp2
    {
        public partial class Form1 : Form
        {
            const int INVALID_HANDLE_VALUE = -1;
            const int PAGE_READWRITE = 0x04;
            //共享内存
            [DllImport("Kernel32.dll", EntryPoint = "CreateFileMapping")]
            private static extern IntPtr CreateFileMapping(IntPtr hFile, //HANDLE hFile,
             UInt32 lpAttributes,//LPSECURITY_ATTRIBUTES lpAttributes,  //0
             UInt32 flProtect,//DWORD flProtect
             UInt32 dwMaximumSizeHigh,//DWORD dwMaximumSizeHigh,
             UInt32 dwMaximumSizeLow,//DWORD dwMaximumSizeLow,
             string lpName//LPCTSTR lpName
             );
    
            [DllImport("Kernel32.dll", EntryPoint = "OpenFileMapping")]
            private static extern IntPtr OpenFileMapping(
             UInt32 dwDesiredAccess,//DWORD dwDesiredAccess,
             int bInheritHandle,//BOOL bInheritHandle,
             string lpName//LPCTSTR lpName
             );
    
            const int FILE_MAP_ALL_ACCESS = 0x0002;
            const int FILE_MAP_WRITE = 0x0002;
    
            [DllImport("Kernel32.dll", EntryPoint = "MapViewOfFile")]
            private static extern IntPtr MapViewOfFile(
             IntPtr hFileMappingObject,//HANDLE hFileMappingObject,
             UInt32 dwDesiredAccess,//DWORD dwDesiredAccess
             UInt32 dwFileOffsetHight,//DWORD dwFileOffsetHigh,
             UInt32 dwFileOffsetLow,//DWORD dwFileOffsetLow,
             UInt32 dwNumberOfBytesToMap//SIZE_T dwNumberOfBytesToMap
             );
    
            [DllImport("Kernel32.dll", EntryPoint = "UnmapViewOfFile")]
            private static extern int UnmapViewOfFile(IntPtr lpBaseAddress);
    
            [DllImport("Kernel32.dll", EntryPoint = "CloseHandle")]
            private static extern int CloseHandle(IntPtr hObject);
    
    
            private Semaphore m_Write;  //可写的信号
            private Semaphore m_Read;  //可读的信号
            private IntPtr handle;     //文件句柄
            private IntPtr addr;       //共享内存地址
            uint mapLength;            //共享内存长
    
            Thread threadRed;
    
            public Form1()
            {
                InitializeComponent();
                //threadRed = new Thread(new ThreadStart(init));
                //threadRed.Start();
                mapLength = 1024;
    
            }
    
            private void button1_Click(object sender, EventArgs e)
            {
                try
                {
                    m_Write = Semaphore.OpenExisting("WriteMap");
                    m_Read = Semaphore.OpenExisting("ReadMap");
                    handle = OpenFileMapping(FILE_MAP_WRITE, 0, "shareMemory");
                    addr = MapViewOfFile(handle, FILE_MAP_ALL_ACCESS, 0, 0, 0);
    
                    m_Write.WaitOne();
                    byte[] sendStr = Encoding.Default.GetBytes(textBox1.Text.ToString() + '\0');
                    //如果要是超长的话，应另外处理，最好是分配足够的内存
                    if (sendStr.Length < mapLength)
                        Copy(sendStr, addr);
    
                    m_Read.Release();
    
    
                }
                catch (WaitHandleCannotBeOpenedException)
                {
                    MessageBox.Show("不存在系统信号量!");
                    return;
                }
            }
    
            static unsafe void Copy(byte[] byteSrc, IntPtr dst)
            {
                fixed (byte* pSrc = byteSrc)
                {
                    byte* pDst = (byte*)dst;
                    byte* psrc = pSrc;
                    for (int i = 0; i < byteSrc.Length; i++)
                    {
                        *pDst = *psrc;
                        pDst++;
                        psrc++;
                    }
                }
            }
    
        }
    }

[20201231101301160.png]: /images/20221120/aa505e9184c647d0a369039eeeb8ed09.png
[20201231101404184.png]: /images/20221120/3a9b63c6ecc74ee793a2f87ee0b23c42.png