为什么MemoryStream.Write在客户端正常却在服务端编译失败？

云上老周

2026-6-20

解决.NET 4.7.2中MemoryStream.Write缺少必需参数的编译错误（CS7036）

问题核心是不同.NET版本的API差异：.NET 8（客户端）的MemoryStream.Write提供了仅传入byte[]的简化重载，但.NET Framework 4.7.2（服务端）的MemoryStream.Write没有这个重载，必须传入三个参数：byte[] buffer、int offset、int count。你的服务端代码里的ms.Write调用不符合.NET 4.7.2的API要求，因此触发CS7036错误。

修改方案

修改服务端PacketBuilder类的WriteString方法，补充offset（传0，从数组起始位置开始写）和count（传数组长度）参数：

public void WriteString(string msg)
{
    var msgLength = msg.Length;
    var lengthBytes = BitConverter.GetBytes(msgLength);
    ms.Write(lengthBytes, 0, lengthBytes.Length); // 补充offset和count参数
    var msgBytes = Encoding.ASCII.GetBytes(msg);
    ms.Write(msgBytes, 0, msgBytes.Length); // 补充offset和count参数
}

修改后的完整服务端代码

using System;
using System.IO;
using System.Text;

namespace ChatServer.Net.IO
{
    class PacketBuilder
    {
        MemoryStream ms;
        public PacketBuilder()
        {
            ms = new MemoryStream();
        }

        public void WriteOpCode(byte opcode)
        {
            ms.WriteByte(opcode);
        }

        public void WriteString(string msg)
        {
            var msgLength = msg.Length;
            var lengthBytes = BitConverter.GetBytes(msgLength);
            ms.Write(lengthBytes, 0, lengthBytes.Length);
            var msgBytes = Encoding.ASCII.GetBytes(msg);
            ms.Write(msgBytes, 0, msgBytes.Length);
        }

        public byte[] GetPacketBytes()
        {
            return ms.ToArray();
        }
    }
}