Adding HtmlHelper NameSpace in Web.Config does not work

问题

Problem No 1:

Hi guys I have started learning ASP.NET MVC , I have made a simple extension method ,like this

namespace MvcTestz  //Project is also named as "MvcTestz"
{
  public static class SubmitButtonHelper //extension method.
  {
    public static string SubmitButton(this HtmlHelper helper,string buttonText)
    {
        return string.Format("<input type=\"submit\" value=\"{0}\">",buttonText);
    }
  }
}

Then I have added namespace of the Custom HtmlHelper in to the Web.Config ,like this

  <namespaces>
    <!--other namespaces-->
    <add namespace="MvcTestz"/>
    <!--other namespaces-->
  </namespaces>

So that I could use intellisense in the razor View ,but it custom Helper didnt showed up in one View (Home/View/About.cshtml).

So in another view (Home/View/Index.cshtml) I added namespace by @using MvcTestz; statement.

Problem No 2:

Upon WebApp execution Home page(Home/View/Index.cshtml) shows input button text without rendering it into HTML.

On the About page (Home/View/About.cshtml) sever generates error. (Click for Enlarged)

Update:

1. Intellisense problem solved , I had to edit the Web.Config present in the View Directory.SOLVED.
2. HtmlString Should be used if I want to render a Html button.SOLVED.

回答1:

Problem 1:

Razor namespaces should be registred in the <system.web.webPages.razor> node in web.config:

 <system.web.webPages.razor>
    <host factoryType="System.Web.Mvc.MvcWebRazorHostFactory, System.Web.Mvc, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />
    <pages pageBaseType="System.Web.Mvc.WebViewPage">
      <namespaces>
        <add namespace="System.Web.Mvc" />
        <add namespace="System.Web.Mvc.Ajax" />
        <add namespace="System.Web.Mvc.Html" />
        <add namespace="System.Web.Routing" />
        <add namespace="MvcTestz"/>

      </namespaces>
    </pages>
  </system.web.webPages.razor>

Problem 2: Use HtmlString instead of string in your helper:

public static HtmlString SubmitButton(this HtmlHelper helper, string buttonText)
{
    return new HtmlString(string.Format("<input type=\"submit\" value=\"{0}\">", buttonText));
}

回答2:

try something like this,

For your extension method, use MvcHtmlString.Create

public static MvcHtmlString MySubmitButton(this HtmlHelper helper, string buttonText)
{
  return MvcHtmlString.Create("<input type='submit' value='" + buttonText + "' />");
}

and to include your reference see below

  <system.web.webPages.razor>
    <namespaces>
        <!- add here.....  -->
        <add namespace="MvcTestz"/>

      </namespaces>        
  </system.web.webPages.razor>

来源：https://stackoverflow.com/questions/11896977/adding-htmlhelper-namespace-in-web-config-does-not-work