將物件當作參數傳入 function，即使沒有特別標註 ref，在 function裡做的修改也是會影響到原本的物件，除非…
除非在 function裡重新 new了一個。
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApplication4
{
class Root
{
public Node n { get; set; }
}
class Node
{
public string p { get; set; }
}
class Program
{
static void Output(object obj)
{
Console.WriteLine(Newtonsoft.Json.JsonConvert.SerializeObject(obj));
}
static void Main(string[] args)
{
Root r = new Root { n = new Node { p = "Main" } };
Output(r);
ChangeRoot1(r);
Output(r);
ChangeRoot2(r);
Output(r);
ChangeRoot3(r);
Output(r);
ChangeRoot4(r);
Output(r);
ChangeRoot5(r);
Output(r);
ChangeRoot6(ref r);
Output(r);
/* output
{"n":{"p":"Main"}}
{"n":{"p":"ChangeRoot1"}}
{"n":{"p":"ChangeRoot2"}}
{"n":{"p":"ChangeRoot2"}}
{"n":{"p":"ChangeRoot4"}}
{"n":{"p":"ChangeRoot4"}}
{"n":{"p":"ChangeRoot6"}}
*/
}
static void ChangeRoot1(Root input)
{
input.n.p = "ChangeRoot1";
}
static void ChangeRoot2(Root input)
{
input.n = new Node { p = "ChangeRoot2" };
}
static void ChangeRoot3(Root input)
{
input = new Root { n = new Node { p = "ChangeRoot3" } };
}
static void ChangeRoot4(Root input)
{
input.n.p = "ChangeRoot4";
input = new Root { n = new Node { p = "ChangeRoot4 ctor" } };
}
static void ChangeRoot5(Root input)
{
input = new Root { n = new Node { p = "ChangeRoot5 ctor" } };
input.n.p = "ChangeRoot5";
}
static void ChangeRoot6(ref Root input)
{
input = new Root { n = new Node { p = "ChangeRoot6" } };
}
}
}