如何在表单元素中呈现输入元素

Question

Antaris RazorEngine v3.9.3在ASP.NET MVC4控制器中用于创建表单元素。 在结果中，html输入元素呈现在表单元素之外。 例如

@using (Html.BeginForm("Test", "Upload"))
{
<input type="file" />
<input type="submit"/>
}

产生

<form action="/Upload/Test" method="post"></form>
<input type="file" />
<input type="submit"/>

虽然正确的结果应该是

<form action="/Upload/Test" method="post">
<input type="file" />
<input type="submit"/>
</form>

RenderScript仅返回输入元素。 <form action="/Upload/Test" method="post">直接写入输出。看起来像BeginForm（）直接写入视图，而Razorengine不捕获其输出。

如何解决这个问题？

查看：

        @Model.RenderScript()

型号：

public IHtmlString RenderScript() {
    var config = new TemplateServiceConfiguration();
    config.BaseTemplateType = typeof(HtmlTemplateBase<>);
    config.Namespaces = new HashSet<string>(new string[] {
                    "System",
                    "System.Collections",
                    "System.Collections.Generic",
                    "System.Globalization",
                    "System.Linq",
                    "System.Web",
                    "System.Web.Mvc",
                    "System.Web.Mvc.Html"
                });
    razor = RazorEngineService.Create(config);
    // In real application colModel is retrieved from database
    var colModel=@"
    @using (Html.BeginForm(""Test"", ""Upload""))
    {
    <input type='file' />
    <input type='submit'/>
    }
    ";
    string res = razor.RunCompile(colmodel, colmodel, typeof(object), new object());
    return MvcHtmlString.Create(res);
}

模板基类：

using RazorEngine.Templating;
using RazorEngine.Text;
using System;
using System.IO;
using System.Web;
using System.Web.Mvc;
using System.Web.WebPages;

public class HtmlTemplateBase<T> : TemplateBase<T>, IViewDataContainer
{
    // http://stackoverflow.com/questions/8561164/razorengine-issues-with-html
    HtmlHelper<T> helper = null;
    ViewDataDictionary viewdata = null;

    public HtmlHelper<T> Html
    {
        get
        { 

            // https://github.com/Antaris/RazorEngine/issues/150
             if (helper == null)
            {
                var p = WebPageContext.Current;
                var wvp = p.Page as WebViewPage;
                var context = wvp != null ? wvp.ViewContext : null;

                context.Writer = this.CurrentWriter;

                helper = new HtmlHelper<T>(context, this);
            }

            return helper;
        }
    }


    public ViewDataDictionary ViewData
    {
        get
        {
            if (viewdata == null)
            {
                viewdata = new ViewDataDictionary();
                viewdata.TemplateInfo = new TemplateInfo() { HtmlFieldPrefix = string.Empty };

                if (this.Model != null)
                {
                    viewdata.Model = Model;
                }
            }
            return viewdata;
        }
        set
        {
            viewdata = value;
        }
    }

    public override void WriteTo(TextWriter writer, object value)
    {
        if (writer == null)
            throw new ArgumentNullException("writer");

        if (value == null) return;
        //try to cast to RazorEngine IEncodedString
        var encodedString = value as IEncodedString;
        if (encodedString != null)
        {
            writer.Write(encodedString);
        }
        else
        {
            var htmlString = value as IHtmlString;
            if (htmlString != null) writer.Write(htmlString.ToHtmlString());
            else
            {
                encodedString = TemplateService.EncodedStringFactory.CreateEncodedString(value);
                writer.Write(encodedString);
            }

        }
    }
}

也在https://github.com/Antaris/RazorEngine/issues/443

中发布