在c# 3.0中,您可以使用以下语法创建匿名类

var o = new { Id = 1, Name = "Foo" };

有没有办法将这些匿名类添加到泛型列表中?

例子:

var o = new { Id = 1, Name = "Foo" };
var o1 = new { Id = 2, Name = "Bar" };

List<var> list = new List<var>();
list.Add(o);
list.Add(o1);

另一个例子:

List<var> list = new List<var>();

while (....)
{
    ....
    list.Add(new {Id = x, Name = y});
    ....
}

当前回答

使用反射

关于此主题的Microsoft文档。

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

var anonObj = new { Id = 1, Name = "Foo" };
var anonType = anonObj.GetType();

var listType = typeof(List<>);

// We know that List<> have only one generic argument, so we do this:
var contructed = listType.MakeGenericType(anonType);

// Create instance
var instance = Activator.CreateInstance(contructed);

// Using it
var list = (IList)instance;
list.Add(anonObj);

对于Dictionary<,>,您需要传递2个参数 例:dicType。MakeGenericType(type1, type2)

对于带有约束的泛型类型(其中T: struct), 我们需要做更多的核实。查看微软文档来学习如何操作。

其他回答

你可以这样做:

var list = new[] { o, o1 }.ToList();

有很多方法来剥这只猫的皮,但基本上它们都在某个地方使用类型推断——这意味着你必须调用一个泛型方法(可能是一个扩展方法)。另一个例子可能是:

public static List<T> CreateList<T>(params T[] elements)
{
     return new List<T>(elements);
}

var list = CreateList(o, o1);

你懂的。

根据这个答案,我提出了两种可以完成任务的方法:

    /// <summary>
    /// Create a list of the given anonymous class. <paramref name="definition"/> isn't called, it is only used
    /// for the needed type inference. This overload is for when you don't have an instance of the anon class
    /// and don't want to make one to make the list.
    /// </summary>
    /// <typeparam name="T"></typeparam>
    /// <param name="definition"></param>
    /// <returns></returns>
#pragma warning disable RECS0154 // Parameter is never used
    public static List<T> CreateListOfAnonType<T>(Func<T> definition)
#pragma warning restore RECS0154 // Parameter is never used
    {
        return new List<T>();
    }
    /// <summary>
    /// Create a list of the given anonymous class. <paramref name="definition"/> isn't added to the list, it is
    /// only used for the needed type inference. This overload is for when you do have an instance of the anon
    /// class and don't want the compiler to waste time making a temp class to define the type.
    /// </summary>
    /// <typeparam name="T"></typeparam>
    /// <param name="definition"></param>
    /// <returns></returns>
#pragma warning disable RECS0154 // Parameter is never used
    public static List<T> CreateListOfAnonType<T>(T definition)
#pragma warning restore RECS0154 // Parameter is never used
    {
        return new List<T>();
    }

你可以使用这些方法

var emptyList = CreateListOfAnonType(()=>new { Id = default(int), Name = default(string) });
//or
var existingAnonInstance = new { Id = 59, Name = "Joe" };
var otherEmptyList = CreateListOfAnonType(existingAnonInstance);

这个答案也有类似的想法,但直到我创建了这些方法之后我才发现它。

您可以创建一个动态列表。

List<dynamic> anons=new List<dynamic>();
foreach (Model model in models)
{
   var anon= new
   {
      Id = model.Id,
      Name=model.Name
   };
   anons.Add(anon);
}

"dynamic"由第一个添加的值初始化。

这就是答案。

string result = String.Empty;

var list = new[]
{ 
    new { Number = 10, Name = "Smith" },
    new { Number = 10, Name = "John" } 
}.ToList();

foreach (var item in list)
{
    result += String.Format("Name={0}, Number={1}\n", item.Name, item.Number);
}

MessageBox.Show(result);

您可以在代码中这样做。

var list = new[] { new { Id = 1, Name = "Foo" } }.ToList();
list.Add(new { Id = 2, Name = "Bar" });