将ASP.NET MVC Razor @helper函数转换为助手类的方法

小编典典

将ASP.NET MVC Razor @helper函数转换为助手类的方法

考虑以下定义了帮助程序的ASP.NET MVC剃刀视图片段

@helper FieldFor<TModel>(Expression<Func<TModel, string>> expression)
{
    <div class="form-group">
        @Html.LabelFor(expression,
                       htmlAttributes:
                           new {@class = "control-label col-md-2"})

        <div class="col-md-10">
            @Html.EditorFor(expression,
                            new
                            {
                                htmlAttributes =
                                new {@class = "form-control"}
                            })
            @Html.ValidationMessageFor(expression, "",
                                       new {@class = "text-danger"})

        </div>
    </div>
}

将其转换为类似以下类的方法的模式是什么：

public static MvcHtmlString FieldFor(this HtmlHelper helper, FieldFor<TModel>(Expression<Func<TModel, string>> expression))
{
   /* Method */
}

我发现的所有示例都集中在生成不依赖于其他HTML帮助器的标记上。

阅读 531

2020-05-19

共1个答案

小编典典

签名必须是

public static MvcHtmlString FieldFor<TModel, TValue>(this HtmlHelper<TModel> helper, Expression<Func<TModel, TValue>> expression)

然后，您可以结合使用TagBuilder和内置的html helper方法来生成html

using System;
using System.Linq.Expressions;
using System.Text;
using System.Web.Mvc;
using System.Web.Mvc.Html;

namespace YourAssembly.Html
{
  public static class FieldHelper
  {
    public static MvcHtmlString FieldFor<TModel, TValue>(this HtmlHelper<TModel> helper, Expression<Func<TModel, TValue>> expression)
    {
      MvcHtmlString label = LabelExtensions.LabelFor(helper, expression, new { @class = "control-label col-md-2" });
      MvcHtmlString editor = EditorExtensions.EditorFor(helper, expression, new { htmlAttributes = new {@class = "form-control"}})
       MvcHtmlString validation = ValidationExtensions.ValidationMessageFor(helper, expression, null, new { @class = "text-danger" });

       StringBuilder html = new StringBuilder();
       html.Append(editor);
       html.Append(validation);
       TagBuilder innerDiv = new TagBuilder("div");
       innerDiv.AddCssClass("col-md-10");
       innerDiv.InnerHtml = html.ToString();
       html = new StringBuilder();
       html.Append(label);
       html.Append(innerDiv.ToString());
       TagBuilder outerDiv = new TagBuilder("div");
       outerDiv.AddCssClass("form-group");
       outerDiv.InnerHtml = html.ToString();
       return MvcHtmlString.Create(outerDiv.ToString());
    }
  }
}

然后，您可以将其添加到所有视图中 web.config

<system.web.webPages.razor>
  <pages pageBaseType="System.Web.Mvc.WebViewPage">
    <namespaces>
      <add namespace="System.Web.Mvc" />
      ....
      <add namespace="YourAssembly.Html" />
    </namespaces>

2020-05-19