Question

我会尽力澄清这一点：

我有一个System.Object类型的对象，其中包含事物列表。事情在运行时确定。目前，我可以找到列表中包含的内容类型，但是我不知道如何访问它们。

这是一个代码示例，其中“ o”是有问题的事物的列表：

示例：

//Assume at this point in code, we have access to "o"
//which is type System.Object

Type thingType = thing.GetType();
Type listType = typeof(List<>);
Type listOfThingsType = listType.MakeGenericType(thingType);

if (o.GetType() == listOfThingsType)
{
    //Now I know o contains a list of things
    //...but how do I access them and work with their members?

    //foreach thing in o
    //   operate on thing through reflection
}

编辑（更多详细信息）： 我正在使用反射来访问事物的属性成员。我不知道属性名称是什么。我不需要能够使用普通的C＃语法。我只需要一种访问事物的方法，这样就可以将它们作为单独的对象使用。

每个HansPassant的可行解决方案。为了澄清下面的评论讨论：

将代码更改为此：

//Assume at this point in code, we have access to "o"
//which is type System.Object

Type thingType = thing.GetType();
Type listType = typeof(List<>);
Type listOfThingsType = listType.MakeGenericType(thingType);

if (o.GetType() == listOfThingsType)
{
    //Now I know o contains a list of things
    //...but how do I access them and work with their members?

    dynamic oList = o;
    foreach(object thing in oList)
    {
        //operate on thing through reflection
    }
}

Answer 1

List<T>实现IList。如果您只需要访问组成序列化列表的实例（或其他任何实例），请使用List而不是List<T>，因为看起来实际类型可能并不重要。当然，这也可能取决于您使用的序列化程序（您在评论中提到了该序列化程序吗？）。

Fiddle

using System;
using System.Collections;
using System.Collections.Generic;
using System.Globalization;

public class Program
{
    public class MyType 
    {
        public string Name {get;set;}
        public MyType(){}
        public MyType(string name) {
          this.Name = name;
        }

        public override string ToString()
        {
            return this.Name ?? "empty";
        }
    }

    public static void Main()
    {
        List<MyType> list = new List<MyType>();
        list.Add(new MyType("One"));
        list.Add(new MyType("Two"));
        DoSomethingWithUnknown(list);
    }

    public static void DoSomethingWithUnknown(object argList)
    {
        var list = (IList)argList;
        foreach(var item in list)
        {
            Console.WriteLine("As object: " + item);
            dynamic itm = item;
            Console.WriteLine("As dynamic: " + itm.Name);
        }
    }
}

Answer 2

谢谢HansPassant，他建议使用动态。

这是解决方案：

//Assume at this point in code, we have access to "o"
//which is type System.Object

Type thingType = thing.GetType();
Type listType = typeof(List<>);
Type listOfThingsType = listType.MakeGenericType(thingType);

if (o.GetType() == listOfThingsType)
{
    //Now I know o contains a list of things
    //...but how do I access them and work with their members?

    dynamic oList = o;
    foreach(object thing in oList)
    {
        //operate on thing through reflection
    }
}

c＃：当T仅存储在类型变量中时，如何访问List <T>中的元素？

2 个答案: