blocks|key|3028972|text|看一下yield关键字--它允许您拥有一个看起来像IEnumerable但实际上对每个返回值进行处理的方法。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3028973|entityMap|0|LINK|mutability|MUTABLE|url|http://msdn.microsoft.com/en-us/library/9k7k7cf0%2528v=VS.100%2529.aspx^0|P|B|3|5|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@$9|O|A|P|B|C]]|D|@$9|Q|A|R|1|S]]|E|$]]|$1|F|3|-4|5|6|7|T|8|@]|D|@]|E|$]]]|G|$H|$5|I|J|K|E|$L|M]]]]

Take a look at the <a href="http://msdn.microsoft.com/en-us/library/9k7k7cf0%28v=VS.100%29.aspx" rel="nofollow">yield</a> keyword -- which will allow you to have a method that looks like an <code>IEnumerable</code> but which actually does processing for each return value.

blocks|key|4629295|text|这个怎么样：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4629296|IEnumerable<Object>+Scan()
{
++++List<Object>+objList+=+new+List<Object>();

++++Action<Object>+action+=+(obj)+=>+{+objList.Add(obj);+};

++++Scan(action);

++++return+objList;
}|code-block|syntax|javascript|4629297|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

How about this one:

<pre><code>IEnumerable&lt;Object&gt; Scan()
{
 List&lt;Object&gt; objList = new List&lt;Object&gt;();

 Action&lt;Object&gt; action = (obj) =&gt; { objList.Add(obj); };

 Scan(action);

 return objList;
}
</code></pre>

blocks|key|962422|text|您应该调查Rx+project+-这允许将事件源作为IEnumerable使用。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|962423|我不确定它是否允许普通的回调以这种方式表示(它针对的是.NET事件)，但它值得一看，因为它应该可以将常规的回调表示为IObservable。|962424|entityMap|0|LINK|mutability|MUTABLE|url|http://msdn.microsoft.com/en-us/devlabs/ee794896^0|Q|B|5|A|0|0|1M|B|0^^$0|@$1|2|3|4|5|6|7|P|8|@$9|Q|A|R|B|C]]|D|@$9|S|A|T|1|U]]|E|$]]|$1|F|3|G|5|6|7|V|8|@$9|W|A|X|B|C]]|D|@]|E|$]]|$1|H|3|-4|5|6|7|Y|8|@]|D|@]|E|$]]]|I|$J|$5|K|L|M|E|$N|O]]]]

You should investigate the <a href="http://msdn.microsoft.com/en-us/devlabs/ee794896" rel="nofollow">Rx project</a> — this allows an event source to be consumed as an <code>IEnumerable</code>.

I'm not sure if it allows vanilla callbacks to be presented as such (it's aimed at .NET events) but it would be worth a look as it should be possible to present a regular callback as an <code>IObservable</code>.

blocks|key|3029035|text|您可以非常简单地使用Reactive来完成此操作：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3029036|class+Program
{
++++static+void+Main(string[]+args)
++++{
++++++++foreach+(var+x+in+CallBackToEnumerable<int>(Scan))
++++++++++++Console.WriteLine(x);
++++}

++++static+IEnumerable<T>+CallBackToEnumerable<T>(Action<Action<T>>+functionReceivingCallback)
++++{
++++++++return+Observable.Create<T>(o+=>
++++++++{
++++++++++++//+Schedule+this+onto+another+thread,+otherwise+it+will+block:
++++++++++++Scheduler.Later.Schedule(()+=>
++++++++++++{
++++++++++++++++functionReceivingCallback(o.OnNext);
++++++++++++++++o.OnCompleted();
++++++++++++});

++++++++++++return+()+=>+{+};
++++++++}).ToEnumerable();
++++}

++++public+static+void+Scan(Action<int>+act)
++++{
++++++++for+(int+i+=+0;+i+<+100;+i%2B%2B)
++++++++{
++++++++++++//+Delay+to+prove+this+is+working+asynchronously.
++++++++++++Thread.Sleep(100);
++++++++++++act(i);
++++++++}
++++}
}|code-block|syntax|javascript|3029037|请记住，这不会处理取消之类的事情，因为回调方法实际上并不允许这样做。一个适当的解决方案需要在外部库部分进行工作。|3029038|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

You can do this quite simply with Reactive:

<pre><code>class Program
{
 static void Main(string[] args)
 {
 foreach (var x in CallBackToEnumerable&lt;int&gt;(Scan))
 Console.WriteLine(x);
 }

 static IEnumerable&lt;T&gt; CallBackToEnumerable&lt;T&gt;(Action&lt;Action&lt;T&gt;&gt; functionReceivingCallback)
 {
 return Observable.Create&lt;T&gt;(o =&gt;
 {
 // Schedule this onto another thread, otherwise it will block:
 Scheduler.Later.Schedule(() =&gt;
 {
 functionReceivingCallback(o.OnNext);
 o.OnCompleted();
 });

 return () =&gt; { };
 }).ToEnumerable();
 }

 public static void Scan(Action&lt;int&gt; act)
 {
 for (int i = 0; i &lt; 100; i++)
 {
 // Delay to prove this is working asynchronously.
 Thread.Sleep(100);
 act(i);
 }
 }
}
</code></pre>

Remember that this doesn't take care of things like cancellation, since the callback method doesn't really allow it. A proper solution would require work on the part of the external library.

blocks|key|4629398|text|下面是一个阻塞枚举器(+Scan方法需要在单独的线程中运行)|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4629399|++++public+class+MyEnumerator+:+IEnumerator<object>
++++{
++++++++private+readonly+Queue<object>+_queue+=+new+Queue<object>();
++++++++private+ManualResetEvent+_event+=+new+ManualResetEvent(false);

++++++++public+void+Callback(object+value)
++++++++{
++++++++++++lock+(_queue)
++++++++++++{
++++++++++++++++_queue.Enqueue(value);
++++++++++++++++_event.Set();
++++++++++++}
++++++++}

++++++++public+void+Dispose()
++++++++{

++++++++}

++++++++public+bool+MoveNext()
++++++++{
++++++++++++_event.WaitOne();
++++++++++++lock+(_queue)
++++++++++++{
++++++++++++++++Current+=+_queue.Dequeue();
++++++++++++++++if+(_queue.Count+==+0)
++++++++++++++++++++_event.Reset();
++++++++++++}
++++++++++++return+true;
++++++++}

++++++++public+void+Reset()
++++++++{
++++++++++++_queue.Clear();
++++++++}

++++++++public+object+Current+{+get;+private+set;+}

++++++++object+IEnumerator.Current
++++++++{
++++++++++++get+{+return+Current;+}
++++++++}
++++}

++++static+void+Main(string[]+args)
++++{
++++++++var+enumerator+=+new+MyEnumerator();
++++++++Scan(enumerator.Callback);

++++++++while+(enumerator.MoveNext())
++++++++{
++++++++++++Console.WriteLine(enumerator.Current);
++++++++}
++++}|code-block|syntax|javascript|4629400|您可以将其封装在一个简单的IEnumerable<Object>中，但我不建议您这样做。IEnumerable列表意味着您可以在同一列表上运行多个枚举器，这在本例中是不能的。|offset|length|style|CODE|4629401|entityMap^0|0|0|D|J|18|B|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@$I|R|J|S|K|L]|$I|T|J|U|K|L]]|9|@]|A|$]]|$1|M|3|-4|5|6|7|V|8|@]|9|@]|A|$]]]|N|$]]

Here is a blocking enumerator (the Scan method needs to run in a separate thread)

<pre><code> public class MyEnumerator : IEnumerator&lt;object&gt;
 {
 private readonly Queue&lt;object&gt; _queue = new Queue&lt;object&gt;();
 private ManualResetEvent _event = new ManualResetEvent(false);

 public void Callback(object value)
 {
 lock (_queue)
 {
 _queue.Enqueue(value);
 _event.Set();
 }
 }

 public void Dispose()
 {

 }

 public bool MoveNext()
 {
 _event.WaitOne();
 lock (_queue)
 {
 Current = _queue.Dequeue();
 if (_queue.Count == 0)
 _event.Reset();
 }
 return true;
 }

 public void Reset()
 {
 _queue.Clear();
 }

 public object Current { get; private set; }

 object IEnumerator.Current
 {
 get { return Current; }
 }
 }

 static void Main(string[] args)
 {
 var enumerator = new MyEnumerator();
 Scan(enumerator.Callback);

 while (enumerator.MoveNext())
 {
 Console.WriteLine(enumerator.Current);
 }
 }
</code></pre>

You could wrap it in a simple <code>IEnumerable&lt;Object&gt;</code>, but I would not recommend it. <code>IEnumerable</code> lists implies that you can run multiple enumerators on the same list, which you can't in this case.

I'm writing a wrapper around a 3rd party library, and it has a method to scan the data it manages. The method takes a callback method that it calls for each item in the data that it finds.

e.g. The method is essentially: <code>void Scan(Action&lt;object&gt; callback);</code>

I want to wrap it and expose a method like <code>IEnumerable&lt;object&gt; Scan();</code>

Is this possible without resorting to a separate thread to do the actual scan and a buffer?

Possible to turn callback calls into IEnumerable

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我正在编写一个围绕第三方库的包装器，它有一个扫描它管理的数据的方法。该方法接受一个回调方法，它为找到的数据中的每一项调用该回调方法。例如，方法本质上是：void Scan(Action<object> callback);我想包装它并公开一个像IEnumerable<object> Scan();这样的方法如果没有单独...

问可以将回调调用转换为IEnumerable
EN

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问可以将回调调用转换为IEnumerableEN