c# - 连接多个 IEnumerable

Question

我正在尝试实现一种方法来连接多个List，例如

List<string> l1 = new List<string> { "1", "2" };
List<string> l2 = new List<string> { "1", "2" };
List<string> l3 = new List<string> { "1", "2" };
var result = Concatenate(l1, l2, l3);

但是我的方法不起作用:

public static IEnumerable<T> Concatenate<T>(params IEnumerable<T> List)
{
    var temp = List.First();
    for (int i = 1; i < List.Count(); i++)
    {
        temp = Enumerable.Concat(temp, List.ElementAt(i));
    }
    return temp;
}

Answer 1

使用SelectMany:

public static IEnumerable<T> Concatenate<T>(params IEnumerable<T>[] lists)
{
    return lists.SelectMany(x => x);
}