blocks|key|590330|text|如果您在任何视图中使用RenderAction，通常用于呈现局部视图，则可以使用它。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|590331|使用[ChildActionOnly]标记它的原因是你需要控制器方法是公共的，这样你就可以用RenderAction调用它，但是你不希望有人能够导航到一个网址(例如/+controller+/SomeChildAction)并直接看到该操作的结果。|590332|entityMap^0|B|C|0|2|H|1A|C|0^^$0|@$1|2|3|4|5|6|7|J|8|@$9|K|A|L|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|M|8|@$9|N|A|O|B|C]|$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|H|3|-4|5|6|7|R|8|@]|D|@]|E|$]]]|I|$]]

You would use it if you are using <code>RenderAction</code> in any of your views, usually to render a partial view.

The reason for marking it with <code>[ChildActionOnly]</code> is that you need the controller method to be public so you can call it with <code>RenderAction</code> but you don't want someone to be able to navigate to a URL (e.g. /Controller/SomeChildAction) and see the results of that action directly.

blocks|key|374693|text|去派对有点晚了，但是...|type|unstyled|depth|inlineStyleRanges|entityRanges|data|374694|其他答案很好地解释了[ChildActionOnly]属性的作用。然而，在大多数示例中，我一直在问自己，当您可以直接在视图中呈现@Html.Partial("_MyParialView")时，为什么还要创建一个新的操作方法来在另一个视图中呈现局部视图。它看起来像是一个不必要的层。然而，随着我的研究，我发现一个好处是子操作可以创建一个不同的模型，并将其传递给部分视图。局部视图所需的模型可能在渲染局部视图的视图的模型中不可用。您可以调用子操作并让操作方法负责创建部分视图所需的模型，而不是修改模型结构来获取必要的对象/属性。|offset|length|style|CODE|374695|这可以派上用场，例如，在_Layout.cshtml中。如果您有一些对所有页面都通用属性，则实现此目的的一种方法是使用一个基本视图模型，并让所有其他视图模型继承它。然后，_Layout可以使用基本视图模型和公共属性。缺点(这是主观的)是，所有视图模型都必须从基本视图模型继承，以保证这些公共属性始终可用。另一种方法是在这些常见的地方呈现@Html.Action。操作方法将为所有页面所共有的部分视图创建一个单独的模型，这不会影响“主”视图的模型。在这种情况下，_Layout页面不需要模型。因此，所有其他视图模型都不需要从任何基本视图模型继承。|374696|我确信使用[ChildActionOnly]属性还有其他原因，但这对我来说似乎是一个很好的理由，所以我想我应该分享一下。|374697|entityMap^0|0|A|H|1S|U|0|C|E|2D|7|4O|C|6E|7|0|5|H|0^^$0|@$1|2|3|4|5|6|7|N|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|O|8|@$D|P|E|Q|F|G]|$D|R|E|S|F|G]]|9|@]|A|$]]|$1|H|3|I|5|6|7|T|8|@$D|U|E|V|F|G]|$D|W|E|X|F|G]|$D|Y|E|Z|F|G]|$D|10|E|11|F|G]]|9|@]|A|$]]|$1|J|3|K|5|6|7|12|8|@$D|13|E|14|F|G]]|9|@]|A|$]]|$1|L|3|-4|5|6|7|15|8|@]|9|@]|A|$]]]|M|$]]

A little late to the party, but...

The other answers do a good job of explaining what effect the <code>[ChildActionOnly]</code> attribute has. However, in most examples, I kept asking myself why I'd create a new action method just to render a partial view, within another view, when you could simply render <code>@Html.Partial("_MyParialView")</code> directly in the view. It seemed like an unnecessary layer. However, as I investigated, I found that one benefit is that the child action can create a different model and pass that to the partial view. The model needed for the partial might not be available in the model of the view in which the partial view is being rendered. Instead of modifying the model structure to get the necessary objects/properties there just to render the partial view, you can call the child action and have the action method take care of creating the model needed for the partial view.

This can come in handy, for example, in <code>_Layout.cshtml</code>. If you have a few properties common to all pages, one way to accomplish this is use a base view model and have all other view models inherit from it. Then, the <code>_Layout</code> can use the base view model and the common properties. The downside (which is subjective) is that all view models must inherit from the base view model to guarantee that those common properties are always available. The alternative is to render <code>@Html.Action</code> in those common places. The action method would create a separate model needed for the partial view common to all pages, which would not impact the model for the "main" view. In this alternative, the <code>_Layout</code> page need not have a model. It follows that all other view models need not inherit from any base view model.

I'm sure there are other reasons to use the <code>[ChildActionOnly]</code> attribute, but this seems like a good one to me, so I thought I'd share.

blocks|key|374718|text|仅供参考，ASP.NET+MVC核心中不提供ChildActionOnly。查看一些信息here|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|374719|entityMap|0|LINK|mutability|MUTABLE|url|http://www.davepaquette.com/archive/2016/01/02/goodbye-child-actions-hello-view-components.aspx^0|18|4|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

FYI, [ChildActionOnly] is not available in ASP.NET MVC Core.
see some info <a href="http://www.davepaquette.com/archive/2016/01/02/goodbye-child-actions-hello-view-components.aspx" rel="noreferrer">here</a>

blocks|key|590426|text|++++public+class+HomeController+:+Controller++
++++{++
++++++++public+ActionResult+Index()++
++++++++{++
++++++++++++ViewBag.TempValue+=+"Index+Action+called+at+HomeController";++
++++++++++++return+View();++
++++++++}++

++++++++[ChildActionOnly]++
++++++++public+ActionResult+ChildAction(string+param)++
++++++++{++
++++++++++++ViewBag.Message+=+"Child+Action+called.+"+%2B+param;++
++++++++++++return+View();++
++++++++}++
++++}++


The+code+is+initially+invoking+an+Index+action+that+in+turn+returns+two+Index+views+and+at+the+View+level+it+calls+the+ChildAction+named+“ChildAction”.

++++@{
++++++++ViewBag.Title+=+"Index";++++
++++}++++
++++<h2>++++
++++++++Index++++
++++</h2>++

++++<!DOCTYPE+html>++++
++++<html>++++
++++<head>++++
++++++++<title>Error</title>++++
++++</head>++++
++++<body>++++
++++++++<ul>++
++++++++++++<li>++++
++++++++++++++++@ViewBag.TempValue++++
++++++++++++</li>++++
++++++++++++<li>@ViewBag.OnExceptionError</li>++++
++++++++++++@*<li>@{Html.RenderAction("ChildAction",+new+{+param+=+"first"+});}</li>@**@++++
++++++++++++@Html.Action("ChildAction",+"Home",+new+{+param+=+"first"+})++++
++++++++</ul>++++
++++</body>++++
++++</html>++


++++++Copy+and+paste+the+code+to+see+the+result+.thanks+|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|590427|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code> public class HomeController : Controller 
 { 
 public ActionResult Index() 
 { 
 ViewBag.TempValue = "Index Action called at HomeController"; 
 return View(); 
 } 

 [ChildActionOnly] 
 public ActionResult ChildAction(string param) 
 { 
 ViewBag.Message = "Child Action called. " + param; 
 return View(); 
 } 
 } 


The code is initially invoking an Index action that in turn returns two Index views and at the View level it calls the ChildAction named “ChildAction”.

 @{
 ViewBag.Title = "Index"; 
 } 
 &lt;h2&gt; 
 Index 
 &lt;/h2&gt; 

 &lt;!DOCTYPE html&gt; 
 &lt;html&gt; 
 &lt;head&gt; 
 &lt;title&gt;Error&lt;/title&gt; 
 &lt;/head&gt; 
 &lt;body&gt; 
 &lt;ul&gt; 
 &lt;li&gt; 
 @ViewBag.TempValue 
 &lt;/li&gt; 
 &lt;li&gt;@ViewBag.OnExceptionError&lt;/li&gt; 
 @*&lt;li&gt;@{Html.RenderAction("ChildAction", new { param = "first" });}&lt;/li&gt;@**@ 
 @Html.Action("ChildAction", "Home", new { param = "first" }) 
 &lt;/ul&gt; 
 &lt;/body&gt; 
 &lt;/html&gt; 


 Copy and paste the code to see the result .thanks 
</code></pre>

When would you use the attribute <code>ChildActionOnly</code>? What is a <code>ChildAction</code> and in what circumstance would you want restrict an action using this attribute?

Using ChildActionOnly in MVC

什么时候会使用attribute ChildActionOnly？什么是ChildAction？在什么情况下，您希望限制使用此属性的操作？

问在MVC中使用ChildActionOnly
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