blocks|key|1609880|text|下面是一个改编自this的示例|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1609881|var+h+=+new+HtmlHelper(new+ViewContext(ControllerContext,+new+WebFormView("omg"),+new+ViewDataDictionary(),+new+TempDataDictionary()),+new+ViewPage());
h.TextBox("myname");|code-block|syntax|javascript|1609882|请注意，这是一个黑客，它可以做到，但我不认为有任何好的理由这样做…|1609883|entityMap|0|LINK|mutability|MUTABLE|url|http://www.brightmix.com/blog/how-to-renderpartial-to-string-in-asp-net-mvc/^0|8|4|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@$A|T|B|U|1|V]]|C|$]]|$1|D|3|E|5|F|7|W|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|X|8|@]|9|@]|C|$]]|$1|K|3|-4|5|6|7|Y|8|@]|9|@]|C|$]]]|L|$M|$5|N|O|P|C|$Q|R]]]]

Here's an example adapted from <a href="http://www.brightmix.com/blog/how-to-renderpartial-to-string-in-asp-net-mvc/" rel="noreferrer">this</a>:

<pre><code>var h = new HtmlHelper(new ViewContext(ControllerContext, new WebFormView("omg"), new ViewDataDictionary(), new TempDataDictionary()), new ViewPage());
h.TextBox("myname");
</code></pre>

Note that this is a hack, it can be done but I don't think there's any good reason to do this...

blocks|key|1610028|text|您可以像这样使用方法：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1610029|public+static+HtmlHelper+GetHtmlHelper(this+Controller+controller)
{
++++var+viewContext+=+new+ViewContext(controller.ControllerContext,+new+FakeView(),+controller.ViewData,+controller.TempData,+TextWriter.Null);
++++return+new+HtmlHelper(viewContext,+new+ViewPage());
}

public+class+FakeView+:+IView
{
++++public+void+Render(ViewContext+viewContext,+TextWriter+writer)
++++{
++++++++throw+new+InvalidOperationException();
++++}
}|code-block|syntax|javascript|1610030|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 use method like this:

<pre><code>public static HtmlHelper GetHtmlHelper(this Controller controller)
{
 var viewContext = new ViewContext(controller.ControllerContext, new FakeView(), controller.ViewData, controller.TempData, TextWriter.Null);
 return new HtmlHelper(viewContext, new ViewPage());
}

public class FakeView : IView
{
 public void Render(ViewContext viewContext, TextWriter writer)
 {
 throw new InvalidOperationException();
 }
}
</code></pre>

blocks|key|1610000|text|HtmlHelper被设计成视图机制的一部分，应该被认为是独立于控制器和模型部分的。我不确定为什么要在控制器中生成控件，因为它的作用是将数据传递给视图以进行呈现。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1610001|我并不是说你不能实现它，但对于好的设计来说，它会更好。|1610002|你能解释一下你正在尝试实现什么，然后我们可以考虑用"MVC方式“来实现它吗？|1610003|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|H|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|I|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|J|8|@]|9|@]|A|$]]|$1|F|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|G|$]]

The HtmlHelper is part of the View mechanism by design and should be considered separate to the Controller and Model parts of MVC. I am not sure why you would want to generate controls inside the controller as it's role is to deliver the Data to the view for rendering.

I am not saying that you cannot achieve it, but for good design it would be better. 

Can you explain what you are trying to achieve and then we could look at doing it in an "MVC way"?

blocks|key|1395173|text|using+System.Web.Mvc;
using+System.Web.Mvc.Html;

var+h+=+new+HtmlHelper<Effort>(new+ViewContext(ControllerContext,+new+WebFormView(ControllerContext,+"omg"),+new+ViewDataDictionary(),+new+TempDataDictionary(),+new+StringWriter()),+new+ViewPage());

h.DisplayFor(e+=>+Model.Efforts[i].Content.Offer.Price1.Value)|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1395174|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>using System.Web.Mvc;
using System.Web.Mvc.Html;

var h = new HtmlHelper&lt;Effort&gt;(new ViewContext(ControllerContext, new WebFormView(ControllerContext, "omg"), new ViewDataDictionary(), new TempDataDictionary(), new StringWriter()), new ViewPage());

h.DisplayFor(e =&gt; Model.Efforts[i].Content.Offer.Price1.Value)
</code></pre>

blocks|key|1610183|text|对于.NET核心2mvc：https://github.com/aspnet/Mvc/issues/7321|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1610184|using+Microsoft.AspNetCore.Mvc;
using+Microsoft.AspNetCore.Mvc.Infrastructure;
using+Microsoft.AspNetCore.Mvc.ModelBinding;
using+Microsoft.AspNetCore.Mvc.Rendering;
using+Microsoft.AspNetCore.Mvc.Routing;
using+Microsoft.AspNetCore.Mvc.ViewEngines;
using+Microsoft.AspNetCore.Mvc.ViewFeatures;
using+Microsoft.AspNetCore.Mvc.ViewFeatures.Internal;
using+Microsoft.Extensions.Options;
using+System.IO;
using+System.Text.Encodings.Web;
using+System.Threading.Tasks;


++++public+class+HelperGenerator
++++{
++++++++private+readonly+IHtmlGenerator+_htmlGenerator;
++++++++private+readonly+ICompositeViewEngine+_compositeViewEngine;
++++++++private+readonly+IModelMetadataProvider+_modelMetadataProvider;
++++++++private+readonly+IViewBufferScope+_viewBufferScope;
++++++++private+readonly+IActionContextAccessor+_actionContextAccessor;
++++++++private+readonly+HtmlHelperOptions+_htmlHelperOptions;

++++++++public+HelperGenerator(IHtmlGenerator+htmlGenerator,+ICompositeViewEngine+compositeViewEngine,+IModelMetadataProvider+modelMetadataProvider,+IViewBufferScope+viewBufferScope,+IActionContextAccessor+actionContextAccessor,+IOptions<MvcViewOptions>+options)
++++++++{
++++++++++++_htmlGenerator+=+htmlGenerator;
++++++++++++_compositeViewEngine+=+compositeViewEngine;
++++++++++++_modelMetadataProvider+=+modelMetadataProvider;
++++++++++++_viewBufferScope+=+viewBufferScope;
++++++++++++_actionContextAccessor+=+actionContextAccessor;
++++++++++++_htmlHelperOptions+=+options.Value.HtmlHelperOptions;
++++++++}
++++++++public+IHtmlHelper+HtmlHelper(ViewDataDictionary+ViewData,+ITempDataDictionary+TempData)
++++++++{
++++++++++++var+helper+=+new+HtmlHelper(_htmlGenerator,+_compositeViewEngine,+_modelMetadataProvider,+_viewBufferScope,+HtmlEncoder.Default,+UrlEncoder.Default);
++++++++++++var+viewContext+=+new+ViewContext(_actionContextAccessor.ActionContext,
+++++++++++++++new+FakeView(),
+++++++++++++++ViewData,
+++++++++++++++TempData,
+++++++++++++++TextWriter.Null,
+++++++++++++++_htmlHelperOptions);
++++++++++++helper.Contextualize(viewContext);
++++++++++++return+helper;
++++++++}
++++++++private+class+FakeView+:+IView
++++++++{
++++++++++++public+string+Path+=>+"View";

++++++++++++public+Task+RenderAsync(ViewContext+context)
++++++++++++{
++++++++++++++++return+Task.FromResult(0);
++++++++++++}
++++++++}
++++}|code-block|syntax|javascript|1610185|确保在服务中注册：|1610186|services.AddSingleton<IActionContextAccessor,+ActionContextAccessor>();|1610187|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/aspnet/Mvc/issues/7321^0|D|15|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@$A|V|B|W|1|X]]|C|$]]|$1|D|3|E|5|F|7|Y|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|Z|8|@]|9|@]|C|$]]|$1|K|3|L|5|F|7|10|8|@]|9|@]|C|$G|H]]|$1|M|3|-4|5|6|7|11|8|@]|9|@]|C|$]]]|N|$O|$5|P|Q|R|C|$S|T]]]]

For .NET Core 2 MVC: <a href="https://github.com/aspnet/Mvc/issues/7321" rel="nofollow noreferrer">https://github.com/aspnet/Mvc/issues/7321</a>

<pre><code>using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.Infrastructure;
using Microsoft.AspNetCore.Mvc.ModelBinding;
using Microsoft.AspNetCore.Mvc.Rendering;
using Microsoft.AspNetCore.Mvc.Routing;
using Microsoft.AspNetCore.Mvc.ViewEngines;
using Microsoft.AspNetCore.Mvc.ViewFeatures;
using Microsoft.AspNetCore.Mvc.ViewFeatures.Internal;
using Microsoft.Extensions.Options;
using System.IO;
using System.Text.Encodings.Web;
using System.Threading.Tasks;


 public class HelperGenerator
 {
 private readonly IHtmlGenerator _htmlGenerator;
 private readonly ICompositeViewEngine _compositeViewEngine;
 private readonly IModelMetadataProvider _modelMetadataProvider;
 private readonly IViewBufferScope _viewBufferScope;
 private readonly IActionContextAccessor _actionContextAccessor;
 private readonly HtmlHelperOptions _htmlHelperOptions;

 public HelperGenerator(IHtmlGenerator htmlGenerator, ICompositeViewEngine compositeViewEngine, IModelMetadataProvider modelMetadataProvider, IViewBufferScope viewBufferScope, IActionContextAccessor actionContextAccessor, IOptions&lt;MvcViewOptions&gt; options)
 {
 _htmlGenerator = htmlGenerator;
 _compositeViewEngine = compositeViewEngine;
 _modelMetadataProvider = modelMetadataProvider;
 _viewBufferScope = viewBufferScope;
 _actionContextAccessor = actionContextAccessor;
 _htmlHelperOptions = options.Value.HtmlHelperOptions;
 }
 public IHtmlHelper HtmlHelper(ViewDataDictionary ViewData, ITempDataDictionary TempData)
 {
 var helper = new HtmlHelper(_htmlGenerator, _compositeViewEngine, _modelMetadataProvider, _viewBufferScope, HtmlEncoder.Default, UrlEncoder.Default);
 var viewContext = new ViewContext(_actionContextAccessor.ActionContext,
 new FakeView(),
 ViewData,
 TempData,
 TextWriter.Null,
 _htmlHelperOptions);
 helper.Contextualize(viewContext);
 return helper;
 }
 private class FakeView : IView
 {
 public string Path =&gt; "View";

 public Task RenderAsync(ViewContext context)
 {
 return Task.FromResult(0);
 }
 }
 }
</code></pre>

Make sure to register in services:

<pre><code>services.AddSingleton&lt;IActionContextAccessor, ActionContextAccessor&gt;();
</code></pre>

blocks|key|1395247|text|如果有人试图在没有控制器的情况下做到这一点(比如在单元测试时)，还有更多的问题需要处理，因为这些方法(我知道，这些方法不是测试场景，但对于该场景)抛出了空异常(ViewContext.ScopeCache)。您可以通过以下方式看到这一点(请注意，所有这些方法都需要形成一个ViewContext实例，这是您插入到HtmlHelper实例的构造函数中的参数之一，因此在该对象上)：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1395248|viewContext.UnobtrusiveJavaScriptEnabled+=+false;|code-block|syntax|javascript|1395249|简单地设置该值会引发许多方法的异常，但这个问题已经为我解决了，请参阅by+this+answer+how+gets+an+HtmlHelper+(另请参阅here)。|1395250|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/a/25216750/264031|1|https://gist.github.com/ErikSchierboom/6da474dcd5751fbbc94c^0|28|M|3S|B|0|0|1P|A|Y|E|0|25|4|1|0^^$0|@$1|2|3|4|5|6|7|W|8|@$9|X|A|Y|B|C]|$9|Z|A|10|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|11|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|12|8|@$9|13|A|14|B|C]]|D|@$9|15|A|16|1|17]|$9|18|A|19|1|1A]]|E|$]]|$1|M|3|-4|5|6|7|1B|8|@]|D|@]|E|$]]]|N|$O|$5|P|Q|R|E|$S|T]]|U|$5|P|Q|R|E|$S|V]]]]

If someone is trying to do this from without a Controller (like when unit testing), there are further problems to deal with, as many of these methods (which I know, were not a testing scenario, but for that scenario) were throwing Null exceptions (<code>ViewContext.ScopeCache</code>). You can see this by the following (note all of these ways require a <code>ViewContext</code> instance to be formed, which is one of the parameters you insert into the constructor of the HtmlHelper instance, so on that object): 

<pre><code>viewContext.UnobtrusiveJavaScriptEnabled = false;
</code></pre>

Simply setting that value throws an exception with many of these methods, but the problem was fixed for me <a href="https://stackoverflow.com/a/25216750/264031">by this answer</a>, see how he gets an <code>HtmlHelper</code> (see also <a href="https://gist.github.com/ErikSchierboom/6da474dcd5751fbbc94c" rel="nofollow noreferrer">here</a>).

Is it possible to use HtmlHelper in a controller, for-example to get the TextBox(...) method? not that I can't write the html that it generates myself, but I just want to understand how this works so I can create the best solution.

Using HtmlHelper in a Controller

单元测试

是否可以在控制器中使用HtmlHelper，例如，获取TextBox(...)方法？并不是说我不能自己编写它生成的html，而是我只是想了解它是如何工作的，这样我就可以创建最佳的解决方案。

问在控制器中使用HtmlHelper
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