Question

我正在关注本教程here

我很难弄清楚如何获取字符串“这是一个测试消息”来存储在内存映射文件中，然后将其拉出另一端。该教程说要使用字节数组。请原谅我，我是新手，先尝试自己。

谢谢，凯文

##Write to mapped file

using System;
using System.IO.MemoryMappedFiles;

class Program1
{
    static void Main()
    {
        // create a memory-mapped file of length 1000 bytes and give it a 'map name' of 'test'
        MemoryMappedFile mmf = MemoryMappedFile.CreateNew("test", 1000);
        // write an integer value of 42 to this file at position 500
        MemoryMappedViewAccessor accessor = mmf.CreateViewAccessor();
        accessor.Write(500, 42);
        Console.WriteLine("Memory-mapped file created!");
        Console.ReadLine(); // pause till enter key is pressed
        // dispose of the memory-mapped file object and its accessor
        accessor.Dispose();
        mmf.Dispose();
    }
}   


##read from mapped file  
using System;
using System.IO.MemoryMappedFiles;
class Program2
{
    static void Main()
    {
        // open the memory-mapped with a 'map name' of 'test'
        MemoryMappedFile mmf = MemoryMappedFile.OpenExisting("test");
        // read the integer value at position 500
        MemoryMappedViewAccessor accessor = mmf.CreateViewAccessor();
        int value = accessor.ReadInt32(500);
        // print it to the console
        Console.WriteLine("The answer is {0}", value);
        // dispose of the memory-mapped file object and its accessor
        accessor.Dispose();
        mmf.Dispose();
    }
}

Answer 1

您可以考虑编写字符串的长度，然后编写字符串的byte []形式例如，如果我想写“Hello”，那么我将其转换为字节：

byte[] Buffer = ASCIIEncoding.ASCII.GetBytes("Hello");

然后在写入内存映射文件时执行以下操作。

MemoryMappedFile mmf = MemoryMappedFile.CreateNew("test", 1000);
MemoryMappedViewAccessor accessor = mmf.CreateViewAccessor();
accessor.Write(54, (ushort)Buffer.Length);
accessor.WriteArray(54 + 2, Buffer, 0, Buffer.Length);

首先读取位置54并读取保存字符串长度的2个字节。然后你可以读取那个长度的数组并将其转换为字符串。

MemoryMappedFile mmf = MemoryMappedFile.CreateNew("test", 1000);
MemoryMappedViewAccessor accessor = mmf.CreateViewAccessor();
ushort Size = accessor.ReadUInt16(54);
byte[] Buffer = new byte[Size];
accessor.ReadArray(54 + 2, Buffer, 0, Buffer.Length); 
MessageBox.Show(ASCIIEncoding.ASCII.GetString(Buffer));

Answer 2

我用它来写字符串的字符：

string contentString = "Hello";
char[] charsToWrite = contentString.ToCharArray();
accessor.WriteArray(0, charsToWrite, 0, charsToWrite.Length);

这写了宽字符。 C＃和C ++程序都能够读取宽字符的数据。

Answer 3

它可以与CreateOrOpen而不是CreateNew一起使用！用相同的代码

MemoryMappedFile mmf = MemoryMappedFile.CreateOrOpen("test", 1000);
MemoryMappedViewAccessor accessor = mmf.CreateViewAccessor();
accessor.Write(54, (ushort)Buffer.Length);
accessor.WriteArray(54 + 2, Buffer, 0, Buffer.Length);

和

MemoryMappedFile mmf = MemoryMappedFile.CreateOrOpen("test", 1000);
MemoryMappedViewAccessor accessor = mmf.CreateViewAccessor();
ushort Size = accessor.ReadUInt16(54);
byte[] Buffer = new byte[Size];
accessor.ReadArray(54 + 2, Buffer, 0, Buffer.Length); 
MessageBox.Show(ASCIIEncoding.ASCII.GetString(Buffer));

将字符串数据写入MemoryMappedFile

3 个答案: