blocks|key|960732|text|不知道你说的转换是什么意思...Action是action委托的泛型声明...如果你想要一个在'object‘上工作的操作委托，你可以这样做：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|960733|var+myAction+=+new+Action<object>(obj=>+...+);|code-block|syntax|javascript|960734|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|$]]

Not sure what you mean by converting... Action is the generic declaration of an action delegate... if you want an action delegate that works on 'object' you would do something like:

<pre><code>var myAction = new Action&lt;object&gt;(obj=&gt; ... );
</code></pre>

blocks|key|1174980|text|我假设你有这样的东西：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1174981|void+Foo(Action<object>+action)+{+}

Action<something>+myaction;|code-block|syntax|javascript|1174982|想要转换我的myaction，这样你就可以把它传递给Foo了。|1174983|这不管用。|1174984|Foo可以将任何对象传递给其类型从object派生的操作。但是myaction只接受从某些东西派生的对象。|1174985|entityMap^0|0|0|0|0|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]]|$1|G|3|H|5|6|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|R|8|@]|9|@]|A|$]]|$1|K|3|L|5|6|7|S|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

I assume you have something like this:

<pre><code>void Foo(Action&lt;object&gt; action) { }

Action&lt;something&gt; myaction;
</code></pre>

And want to convert myaction so you can pass it to Foo.

That doesn't work.

Foo can pass any object to the action whose type derives from object. But myaction accepts only objects that derive from something.

blocks|key|1175060|text|以下是您所要求的示例(可以在最后一行添加类型检查，以正确处理无效的强制转换异常，以使用户更友好)：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1175061|public+Action<object>+Convert<T>(Action<T>+myActionT)
{
++++if+(myActionT+==+null)+return+null;
++++else+return+new+Action<object>(o+=>+myActionT((T)o));
}|code-block|syntax|javascript|1175062|也许你可以给出更多关于这项任务的细节，因为现在它看起来有点奇怪。|1175063|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|$]]

Here's a sample of what you ask for (type check can be added in last line to properly handle invalid cast exception to be more user-friendly):

<pre><code>public Action&lt;object&gt; Convert&lt;T&gt;(Action&lt;T&gt; myActionT)
{
 if (myActionT == null) return null;
 else return new Action&lt;object&gt;(o =&gt; myActionT((T)o));
}
</code></pre>

May be you can give more details about the task though, because right now it looks a bit odd.

blocks|key|960904|text|我今天正在寻找一种方法来做到这一点，偶然发现了这篇文章。真的，我找到的唯一简单的方法就是将Action包装在一个新的Action中。在我的例子中，我将操作推入并发字典中，然后按类型检索它们。有效地，我正在处理一个消息队列，其中可以定义操作来处理具有特定类型输入的消息。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|960905|var+_actions+=+new+ConcurrentDictionary<Type,+Action<object>>();
Action<string>+actionStr+=+s+=>+Console.WriteLine(s);
var+actionObj+=+new+Action<object>(obj+=>+{+var+castObj+=+(V)Convert.ChangeType(obj,+typeof(V));+actionStr(castObj);+}+);
_actions.TryAdd(typeof(string),+actionObj);|code-block|syntax|javascript|960906|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|$]]

I was looking for a way to do this today and stumbled upon this post. Really, the only simple way I found to do it was to wrap Action&lt;string&gt; within a new Action&lt;object&gt;. In my case, I was pushing my Actions into a Concurrent Dictionary, and then retrieving them by type. Effectively, I was processing a queue of messages where actions could be defined to handle messages with a particular typed input.

<pre><code>var _actions = new ConcurrentDictionary&lt;Type, Action&lt;object&gt;&gt;();
Action&lt;string&gt; actionStr = s =&gt; Console.WriteLine(s);
var actionObj = new Action&lt;object&gt;(obj =&gt; { var castObj = (V)Convert.ChangeType(obj, typeof(V)); actionStr(castObj); } );
_actions.TryAdd(typeof(string), actionObj);
</code></pre>

blocks|key|960928|text|您可以像这样添加泛型参数|type|unstyled|depth|inlineStyleRanges|entityRanges|data|960929|++++Action<object>+Function<T>(Action<T>+act)+where+T+:+class
++++{
++++++++return+(Action<object>)act;
++++}|code-block|syntax|javascript|960930|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|$]]

You can add generic parameter like this
<pre><code> Action&lt;object&gt; Function&lt;T&gt;(Action&lt;T&gt; act) where T : class
 {
 return (Action&lt;object&gt;)act;
 }
</code></pre>

I am stuck.

How do I convert the <code>Action&lt;T&gt; to an Action&lt;Object&gt;</code> in C#?

Regards
Magnus

Convert Action<T> to Action<object>

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