使用protobuf-net基于类型变量动态反序列化类

Question

我正在尝试创建一个标准化的事件消息系统（用于我的游戏服务器和客户端），该系统使用protobuf网络通过UDP套接字发送数据，以实现快速和最佳的数据传输。

目前，我正在尝试发送一个事件类，它可能是PlayerIntentEvent类，也可能是OnConnectionEvent类（存在更多的事件，这些只是一个例子）。

我正在发送一个字节[]，其中第一个字节表示事件类（用于取消序列化），其余字节[]是类本身，用protobuf-net序列化。这部分工作正常。我的问题在接收部分我想基于类型变量动态反序列化一个类

经过一周的探索和尝试，我找不到一种方法来做到这一点。

我的当前设置：

事件类型的常量：

public static class EventTypes {
    public static byte OnConnection = 1;
    public static byte OnError = 2;
    public static byte OnPlayerIntent = 3;
}

服务器的事件映射：

public static class Constants {
    public static Dictionary<byte, Type> EventDataCastDictionary = new Dictionary<byte, Type> {
        { EventTypes.OnConnection, null },
        { EventTypes.OnPlayerIntent, typeof (PlayerIntentEvent) }
    };
    public static readonly IPEndPoint ClientEndPoint = new IPEndPoint(IPAddress.Any, 0);
    public static readonly IPEndPoint ServerEndPoint = new IPEndPoint(IPAddress.Any, 9423);
}

出于测试目的，我创建了一个sender方法，该方法只将PlayerIntentEvent发送到服务器：

public void SendPlayerIntent(PlayerIntentEvent packet) {
        try {
            byte[] bytes;
            using (MemoryStream stream = new MemoryStream()) {
                stream.WriteByte(EventTypes.OnPlayerIntent);
                ProtoBuf.Serializer.Serialize<PlayerIntentEvent>(stream, packet);
                bytes = stream.ToArray();
            }
            //client is an instance of UdpClient
            client.Send(bytes, bytes.Length, serverEndPoint);
        } catch (Exception err) {
            throw err;
        }
    }

我的服务器的接收端：

using System;
using System.IO;
using System.Net.Sockets;
using System.Threading.Tasks;
using ProtoBuf;
abstract class UdpBase {
    protected UdpClient Client;
    protected UdpBase() {
        Client = new UdpClient();
    }
    public async Task<Received> Receive() {
        var receivedStream = await Client.ReceiveAsync();
        NetworkPacket networkPacket = new NetworkPacket();
        object packet = null;
        //Getting the class type from the first byte of the array
        Type eventType = Constants.EventDataCastDictionary[receivedStream.Buffer[0]];
        //----PROBLEM
        //Here I am reading only the class
        using (var stream = new MemoryStream(receivedStream.Buffer, 1, receivedStream.Buffer.Length - 1)) {
        //I want to put a type from my mapping in place of the ?????*
        //I have tried using eventType variable, but the code does not compile
            packet = Serializer.Deserialize<?????*>(stream);
        }
        //----END OF PROBLEM    
        //The return statement is not finished
        return new Received();
    }
}

更新：

在使用大卫的修改后，我已经开始接收

Exception thrown: 'ProtoBuf.ProtoException' in protobuf-net.dll
Exception thrown: 'ProtoBuf.ProtoException' in mscorlib.dll

更新2:

我的事件类缺少一个默认的无参数构造函数。现在一切都在工作，即使没有Convert.ChangeType。：）

Answer 1

您可以使用非泛型重载并强制转换结果：

Type eventType = Constants.EventDataCastDictionary[receivedStream.Buffer[0]];
using (var stream = new MemoryStream(receivedStream.Buffer, 1, 
        receivedStream.Buffer.Length - 1)) {
    packet =  Convert.ChangeType(Serializer.Deserialize(eventType, stream),
                                 eventType);
}