如何在 C# 中将类设为 IEnumerable？
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How to make the class as an IEnumerable in C#?
提问by Ivan Prodanov
So I've got a class and a generic List inside of it, but it is private.
所以我有一个类和一个通用列表，但它是私有的。
class Contacts
{
List<Contact> contacts;
...
}
I want to make the class work as this would do:
我想让这门课像这样工作：
foreach(Contact in contacts) .... ;
like this (not working):
像这样（不工作）：
Contacts c;
foreach(Contact in c) .... ;
In the example above the Contact class instance c has to yield return every item from contacts(private member of c)
在上面的例子中，Contact 类实例 c 必须从contacts（c 的私有成员）返回每个项目
How do I do it? I know it has to be IEnumerable with yield return, but where to declare that?
我该怎么做？我知道它必须是具有收益回报的 IEnumerable，但是在哪里声明呢？
回答by LightStriker
Implement the interface IEnumerable:
实现接口IEnumerable：
class Contacts : IEnumerable<Contact>
{
List<Contact> contacts;
#region Implementation of IEnumerable
public IEnumerator<Contact> GetEnumerator()
{
return contacts.GetEnumerator();
}
IEnumerator IEnumerable.GetEnumerator()
{
return GetEnumerator();
}
#endregion
}
回答by Tigran
public class Contacts: IEnumerable
{
......
public IEnumerator GetEnumerator()
{
return contacts.GetEnumerator();
}
}
Should do a trick for you.
应该为你做一个伎俩。
回答by Tim Schmelter
Or return an IEnumerator<Contact>by providing a GetEnumeratormethod:
或者IEnumerator<Contact>通过提供一个GetEnumerator方法返回一个：
class Contacts
{
List<Contact> contacts;
public IEnumerator<Contact> GetEnumerator()
{
foreach (var contact in contacts)
yield return contact;
}
}
The foreachlooks for GetEnumerator. Have a look here for the language specification details regarding this: https://stackoverflow.com/a/3679993/284240
在foreach验看GetEnumerator。在此处查看有关此的语言规范详细信息：https: //stackoverflow.com/a/3679993/284240
回答by flaugh
class Program
{
static void Main(string[] args)
{
var list = new Contacts();
var a = new Contact() { Name = "a" };
var b = new Contact() { Name = "b" };
var c = new Contact() { Name = "c" };
var d = new Contact() { Name = "d" };
list.ContactList = new List<Contact>();
list.ContactList.Add(a);
list.ContactList.Add(b);
list.ContactList.Add(c);
list.ContactList.Add(d);
foreach (var i in list)
{
Console.WriteLine(i.Name);
}
}
}
class Contacts : IEnumerable<Contact>
{
public List<Contact> ContactList { get; set; }
public IEnumerator<Contact> GetEnumerator()
{
return ContactList.GetEnumerator();
}
IEnumerator IEnumerable.GetEnumerator()
{
return ContactList.GetEnumerator();
}
}
class Contact
{
public string Name { get; set; }
}
回答by Stephanie
How about just extending List<Contact>
只是延长怎么样 List<Contact>
If you don't want to extend any other class its a very simple, fast option:
如果您不想扩展任何其他类，这是一个非常简单、快速的选择：
class Contacts :List<Contact>
{
}
