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
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);
其他回答
我很惊讶居然没有人建议集合初始化器。这种方法只能在创建列表时添加对象，因此得名，但它似乎是最好的方法。不需要创建一个数组，然后将其转换为列表。
var list = new List<dynamic>()
{
new { Id = 1, Name = "Foo" },
new { Id = 2, Name = "Bar" }
};
你可以总是使用对象而不是动态，但尽量保持在一个真正的通用方式，那么动态更有意义。
试试这个:
var result = new List<object>();
foreach (var test in model.ToList()) {
result.Add(new {Id = test.IdSoc,Nom = test.Nom});
}
我通常使用以下方法;主要是因为你从一个空列表开始。
var list = Enumerable.Range(0, 0).Select(e => new { ID = 1, Name = ""}).ToList();
list.Add(new {ID = 753159, Name = "Lamont Cranston"} );
//etc.
最近，我把它写成了这样:
var list = Enumerable.Repeat(new { ID = 1, Name = "" }, 0).ToList();
list.Add(new {ID = 753159, Name = "Lamont Cranston"} );
使用repeat方法还可以执行以下操作:
var myObj = new { ID = 1, Name = "John" };
var list = Enumerable.Repeat(myObj, 1).ToList();
list.Add(new { ID = 2, Name = "Liana" });
．．这将为您提供已经添加了第一项的初始列表。
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。
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);
