C#类型转换之自定义隐式转换和显式转换

//================定义类型和方法================
class Robot
{
    public int Id { get; set; }
    public string Name { get; set; }

    public Robot(int id, string name)
    {
        Id = id;
        Name = name;
    }

    #region 其他类型->本类

    //隐式转换
    public static implicit operator Robot(string name)
    {
        return new Robot(101, name);
    }

    //显式转换
    public static explicit operator Robot(int id)
    {
        return new Robot(id, "miku");
    }

    #endregion

    #region 本类->其他类型

    //隐式转换
    public static implicit operator string(Robot robot)
    {
        return robot.Name;
    }

    //显式转换
    public static explicit operator int(Robot robot)
    {
        return robot.Id;
    }

    #endregion
}

//================测试代码================
#region 其他类型->本类

string gumiStr = "gumi";
Robot gumi001 = gumiStr; //隐式转换
Console.WriteLine("隐式转换：gumi001 : {0}", JsonConvert.SerializeObject(gumi001));

int lukaId = 1004;
Robot luka001 = (Robot)lukaId; //显式转换
Console.WriteLine("显式转换：luka001 : {0}", JsonConvert.SerializeObject(luka001));

#endregion

#region 其他类型->本类

Robot miku001 = new Robot(1001, "miku10001");
//隐式转换
string mikuName = miku001;
//显式转换
int mikuId = (int)miku001;

Console.WriteLine("隐式转换：miku001 Name: {0}", mikuName);
Console.WriteLine("显式转换：miku001 Id: {0}", mikuId);

#endregion

using System;
using System.Linq;
using System.Collections.Generic;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
					
public class Program
{
	public static void Main()
	{
		var json = "[1,[[2,2],[2,2],[2,2],[2,2]]]";
		var root = JsonConvert.DeserializeObject<Root>(json);
		foreach(var ele in root)
		{
			if(ele.SingleValue.HasValue)
			{//有值，原始数据为 1
				Console.WriteLine(ele.SingleValue.Value);
			}else
			{//原始数据为 二维数组
				Console.WriteLine(string.Join(" ",ele.Select(x=>string.Join(",",x))));
			}
		}
		Console.WriteLine(JsonConvert.SerializeObject(root));
	}
}

class Root : List<Element> { }
[JsonConverter(typeof(CConverter))]
class Element : List<List<long>>
{
    //该属性，存放 1 。后续可以通过判断该属性是否有值来得知原始数据的情况
	public long? SingleValue { get; set; }

    //遇到 1 ，隐式转换为 该类型，其中 1 被存放到SingleValue属性
	public static implicit operator Element(long d)
	{
		return new Element { SingleValue = d };
	}
}

public class CConverter : JsonConverter
{
	public override bool CanConvert(Type objectType)
	{
		return (objectType == typeof(Element));
	}

	public override bool CanRead  { get { return false; } }
	public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
	{
		throw new NotImplementedException();
	}

	public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
	{
		var ele = value as Element;
		var token = ele.SingleValue.HasValue ? JToken.FromObject(ele.SingleValue.Value) : JToken.FromObject(ele.ToList());
		token.WriteTo(writer);
	}

	public override bool CanWrite { get { return true; } }
}