//迭代器是延迟计算的，用foreach时，自动调用MoveNext时调用
private static IEnumerable <string> WhereListWithIterator(FriendColl ff)
{
for (var i = 0; i < ff.Count; i++)
{
yield return(ff[i].Name);
}
}
private static void ChildTest1()
{
FriendColl friends = new FriendColl();
friends[1] = new Friend("fwq");
friends.Add(new Friend("zxc", 100));
foreach (Friend f in friends)
{
Console.WriteLine(f.Name + " " + f.Age);
}
Console.WriteLine("---------------------------------------------");
Console.WriteLine("使用yield return 返回一个枚举序列");
foreach (int ii in WithIterator())
{
Console.WriteLine(ii);
}
var tempList = WhereListWithIterator(friends);
foreach (var ss in tempList)
{
Console.WriteLine(ss);
}
Console.ReadKey();
}
private Friend current; //当前指向的元素
internal FriendCollIterator(FriendColl fcol)
{
friends = fcol;
index = 0;
}
