ASP.NET MVC：自定义HTML佣工剃刀 [英] ASP.NET MVC: Custom Html Helpers in Razor

问题描述

剃刀使用时，我有HTML辅助困难。说佣工MVC 2工作正常的网页表单视图引擎。但不是在剃刀。我在运行时得到的错误是：

I am having difficulty with Html Helpers when used with Razor. Said helpers worked fine in MVC 2 with the web form view engine. But not in razor. The error I get at runtime is:

Compiler Error Message: CS1502: The best overloaded method match for 'System.Web.WebPages.WebPageExecutingBase.Write(System.Web.WebPages.HelperResult)' has some invalid arguments

Source Error:


Line 1:  @using Wingspan.Web.Mvc;
Line 2:  @Html.IncrementalMenu(MenuBlock.Site)

拓展显示详细编译器输出显示：

Expanding the Show Detailed Compiler Output reveals:

d:\...\Views\Shared\MenuTop.cshtml(2,1): error CS1502: The best overloaded method match for 'System.Web.WebPages.WebPageExecutingBase.Write(System.Web.WebPages.HelperResult)' has some invalid arguments
d:\...\Views\Shared\MenuTop.cshtml(2,7): error CS1503: Argument 1: cannot convert from 'void' to 'System.Web.WebPages.HelperResult'

这表明，我认为剃刀不喜欢我的帮手，IncrementalMenu，返回void（在MVC 2的Web表单引擎意见工作正常）。

That indicates to me that razor doesn't like my helper, IncrementalMenu, returning void (which works fine in MVC 2 web form engine views).

我得到在编译时没有错误，但code（@ Html.IncrementalMenu（...））的线是红色，下面的消息强调：

I get no errors at Compile time, although the line of code (@Html.IncrementalMenu(...)) is red underlined with the following message:

Cannot implicitly convert type 'void' to 'object'

IncrementalMenu处于Wingspan.Web.Mvc命名空间。它的签名如下：

IncrementalMenu is in the Wingspan.Web.Mvc namespace. It's signature is as follows:

public static void IncrementalMenu(this HtmlHelper html, MenuBlock menuBlock)
{
    // Uses an HtmlTextWriter to render a menu from the sitemap
}

我炸飞，如果我知道什么是错...

I'm blowed if I know what is wrong...

PS：

该MenuBlock参数仅标识菜单应如何呈现一个枚举。不要在此注视，因为这是很好。

The MenuBlock parameter is just an enum that identifies how the menu should render. Don't fixate on this as that is fine.

推荐答案

您可以打电话给你的帮助是这样的：

You can call your helper like this:

@{ Html.IncrementalMenu(MenuBlock.Site); }

WebForms的语法

WebForms syntax

<% Html.IncrementalMenu(MenuBlock.Site); %>

您只需拨打你的方法，并返回值（如果有的话）将被忽略。

You just call your method, and the return value (if there is any) is ignored.

code这样需要一个返回值，返回值写入HTML流：

Code like this expects a return value, and writes the return value to the html stream:

@Html.YourHelper()

Web表单语法：

Webforms syntax:

<%: Html.YourHelper() %>

同样的，如果结果值= IHtmlString：

The same, if result value != IHtmlString:

<%= Server.HtmlEncode(Html.YourHelper()) %>

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