c# - MVC Html 扩展返回字符串而不是 html 标记？

Question

如果我有这样的扩展名:

 public static string ImageLink(this HtmlHelper htmlHelper,
                                      string imgSrc, 
                                      string alt, 
                                      string actionName,
                                      string controllerName, 
                                      object routeValues, 
                                      object htmlAttributes, 
                                      object imgHtmlAttributes)
  {

     return @"<img src=""../../Content/images/english.png"" /> ";
  }

我在这样的局部 View 中使用它:

@Html.ImageLink("../../Content/images/english.png","English", "ChangeCulture", "Account", new { lang = "en", returnUrl = this.Request.RawUrl }, null,null)

我有这样的输出:

知道为什么吗？

Answer 1

发生这种情况的原因是因为 Razor 中的 @ 运算符会自动对 HTML 进行编码。如果你想避免这种编码，你需要使用 IHtmlString:

public static IHtmlString ImageLink(
    this HtmlHelper htmlHelper,
    string imgSrc, 
    string alt, 
    string actionName,
    string controllerName, 
    object routeValues, 
    object htmlAttributes, 
    object imgHtmlAttributes
)
{
    return MvcHtmlString.Create(@"<img src=""../../Content/images/english.png"" />");
}

如果这样写，显然会更正确(并且在所有情况下都有效，无论从哪里以及如何调用这个助手):

public static IHtmlString ImageLink(
    this HtmlHelper htmlHelper,
    string imgSrc,
    string alt,
    string actionName,
    string controllerName,
    object routeValues,
    object htmlAttributes,
    object imgHtmlAttributes
)
{
    var img = new TagBuilder("img");
    var urlHelper = new UrlHelper(htmlHelper.ViewContext.RequestContext);
    img.Attributes["src"] = urlHelper.Content("~/Content/images/english.png");
    // Don't forget that the alt attribute is required if you want to have valid HTML
    img.Attributes["alt"] = "English flag"; 
    return MvcHtmlString.Create(img.ToString(TagRenderMode.SelfClosing));
}

然后

@Html.ImageLink("../../Content/images/english.png","English", "ChangeCulture", "Account", new { lang = "en", returnUrl = this.Request.RawUrl }, null,null)

将正常工作。

作为替代方案，如果您无法修改您可以使用 @Html.Raw 的助手:

@Html.Raw(Html.ImageLink("../../Content/images/english.png","English", "ChangeCulture", "Account", new { lang = "en", returnUrl = this.Request.RawUrl }, null,null))