C# 操作非持久化内存映射文件

news2024/11/15 8:46:22

写在前面

代码实现

进程A

进程B

进程C

调用示例

总结

写在前面

多个进程之间，通过操作未映射到磁盘上现有文件的内存映射文件，可以实现数据共享和类似进程间通讯的功能。以下示例展示了使用三个独立进程，先各自将布尔值写入内存映射文件，然后再由其中一个全部读取出来的功能；示例代码主要来自微软官方教程。

代码实现

进程A


using System.IO.MemoryMappedFiles;

Console.WriteLine("我是独立进程A");

using MemoryMappedFile mmf = MemoryMappedFile.CreateNew("test_mem_map_file", 10000);

bool mutexCreated;
Mutex mutex = new Mutex(true, "testmapmutex", out mutexCreated);
using (MemoryMappedViewStream stream = mmf.CreateViewStream())
{
    BinaryWriter writer = new BinaryWriter(stream);
    writer.Write(1);
}
mutex.ReleaseMutex();

Console.WriteLine("请启动进程 B 并按下确认键以继续运行.");
Console.ReadLine();

Console.WriteLine("请启动进程 C 并按下确认键以继续运行.");
Console.ReadLine();

mutex.WaitOne();
using (MemoryMappedViewStream stream = mmf.CreateViewStream())
{
    BinaryReader reader = new BinaryReader(stream);
    Console.WriteLine("进程 A 写入的内容: {0}", reader.ReadBoolean());
    Console.WriteLine("进程 B 写入的内容: {0}", reader.ReadBoolean());
    Console.WriteLine("进程 C 写入的内容: {0}", reader.ReadBoolean());
}
mutex.ReleaseMutex();


Console.ReadLine();

进程B

using System.IO.MemoryMappedFiles;

Console.WriteLine("我是独立进程B");

try
{
    using MemoryMappedFile mmf = MemoryMappedFile.OpenExisting("test_mem_map_file");
    Mutex mutex = Mutex.OpenExisting("testmapmutex");
    mutex.WaitOne();

    using (MemoryMappedViewStream stream = mmf.CreateViewStream(1, 0))
    {
        BinaryWriter writer = new BinaryWriter(stream);
        writer.Write(0);
    }
    mutex.ReleaseMutex();
}
catch (FileNotFoundException)
{
    Console.WriteLine("内存映射文件不存在. 请先运行进程A.");
}

进程C

using System.IO.MemoryMappedFiles;

Console.WriteLine("我是独立进程C");

try
{
    using MemoryMappedFile mmf = MemoryMappedFile.OpenExisting("test_mem_map_file");
    Mutex mutex = Mutex.OpenExisting("testmapmutex");
    mutex.WaitOne();

    using (MemoryMappedViewStream stream = mmf.CreateViewStream(2, 0))
    {
        BinaryWriter writer = new BinaryWriter(stream);
        writer.Write(0);
    }
    mutex.ReleaseMutex();
}
catch (FileNotFoundException)
{
    Console.WriteLine("内存映射文件不存在. 请先运行进程A,再运行进程B.");
}