c# - 如何将方法返回类型设置为与其当前所在的类相同

Question

中级 C# 程序员在这里。我正在编写一个网络包装器，并希望每种类型的数据包都能够定义自己的“OpenPacket”方法，该方法将接收与当前类相同类型的类的参数。我还想要另一种方法“WriteToPacket”，它将返回与其当前类相同类型的数据包。

例如。MessagePacket 类的WriteToPacket 将返回一个MessagePacket。我会使用继承并只返回一个数据包类型，但每个数据包都有不同的变量。另外，我正在将它开发为一个库，所以我希望能够在 dll 之外定义新的数据包类型。

我有一个数据包类型的接口

public interface IPacket_Type<T> where T : class
{
    T OpenPacketFromMessage(NetIncomingMessage msg) ;
    NetOutgoingMessage PackPacketIntoMessage(NetOutgoingMessage msg, T packet);
}

我将其用作数据包的一部分

public class TestPacket : Packet, IPacket_Type<TestPacket> {
    public int testInt;

    public TestPacket(string packet_name) : base(packet_name){}

    public TestPacket OpenPacketFromMessage(NetIncomingMessage msg)
    {
        TestPacket packet = new TestPacket(packet_name);
        packet.testInt = msg.ReadInt32();

        return packet;
    }

    public NetOutgoingMessage PackPacketIntoMessage(NetOutgoingMessage msg, TestPacket packet)
    {
        msg.Write(packet_name);
        msg.Write(packet.testInt);
        return msg;
    }
}

在服务器端收到类名后，我希望能够实例化这样的类。例如，制作一个 TestPacket 实例而不是一个数据包。我考虑这样做的一种方法是创建一个返回其当前类型的数据包类，因此允许我将其用作基础，始终返回类的类型。

任何帮助将不胜感激，谢谢！

标签： c#classnetworking

Answer 1

在下面的代码中，我将向您展示如何使用同一类的实例的一些示例：

public class Sample {
    // This method returns the same instance of the sample class
    public Sample ReturnSampleInstance() {
        return this;
    }

    // This method creates a completely new instance of the class with other data
    public Sample ReturnAnotherSampleInstance() {
        var sample = new Sample();
        // Perform some logic with the new sample instance or fill up some data
        return sample;
    }

    // This method receives an instance of the same class and returns it
    public Sample ReceivesSampleInstanceAndReturnIt(Sample sampleInstance) {
        return sampleInstance;
    }
}

如果你想使用一个接口并且接口的方法有一个返回类型作为实现类，你可以这样做：

// Generic Interface 
public interface ISample<Timplementation> {
    Timplementation GetCurrentInstanceUsingAnInterface();
}

// Class that implements the interface and passes itself to the ISample interface as a generic parameter
public class Sample : ISample<Sample> {
    // This method returns the same instance of the sample class
    public Sample ReturnSampleInstance() {
        return this;
    }

    // This method creates a completely new instance of the class with other data
    public Sample ReturnAnotherSampleInstance() {
        var sample = new Sample();
        // Perform some logic with the new sample instance or fill up some data
        return sample;
    }

    // This method receives an instance of the same class and returns it
    public Sample ReceivesSampleInstanceAndReturnIt(Sample sampleInstance) {
        return sampleInstance;
    }

    // Get the current instance of the class through the method of the interface
    public Sample GetCurrentInstanceUsingAnInterface() {
        return this;
    }
}