C#初始化列表属性

Question

我有以下类...我如何初始化一些值
我的问题是,我如何在Main上初始化RootObject与一些值例如

    Rootobject robj = new Rootobject();
    robj.inchistor.Add()     



    using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Text;

    namespace JsonSample3
    {

        public class Customerinfo
        {
            public string customername { get; set; }
            public string address { get; set; }
            public string postcode { get; set; }
        }

        public class Inchistory
        {

            public Customerinfo customerinfo { get; set; }
            public string r { get; set; }
            public string reference { get; set; }
            public string region { get; set; }

        }

        public class RootObject
        {
            public List<Inchistory> inchistory { get; set; }
        }


    }

    class Program
    {
            static void Main(string[] args)
            {
               RootObject robj = new RootObject{ r = "", }

            }
    }



   Am having above classes namely CustomerInfo, Inchistory and Rootobject

Answer 1

任何引用类型的默认值为null.因此,我假设您在NullReferenceException尝试添加值时获得了一个.您可以将list属性初始化为对象构造函数中的空列表:

public class RootObject
{
    public List<Inchistory> inchistory { get; set; }

    public RootObject()
    {
        inchistory = new List<Inchistory>();
    }
}

现在任何实例RootObject都默认有一个有效(空)列表,允许你添加它:

Rootobject robj = new Rootobject();
robj.inchistor.Add(someInstanceOfInchistory);