我正在创建一个自定义HTML Tag Helper：

public class CustomTagHelper : TagHelper
    {
        [HtmlAttributeName("asp-for")]
        public ModelExpression DataModel { get; set; }

        public override async Task ProcessAsync(TagHelperContext context, TagHelperOutput output)
        {
            string content = RazorRenderingService.Render("TemplateName", DataModel.Model);
            output.Content.SetContent(content);
        }
    }

如何以编程方式呈现部分视图并在TagHelper.ProcessAsync中以字符串形式获取呈现的内容？
我应该请求注入IHtmlHelper吗？
是否有可能获得剃须刀引擎的参考？

解决方法:

可以在自定义TagHelper中请求注入IHtmlHelper：

public class CustomTagHelper : TagHelper
    {
        private readonly IHtmlHelper html;

        [HtmlAttributeName("asp-for")]
        public ModelExpression DataModel { get; set; }

        [HtmlAttributeNotBound]
        [ViewContext]
        public ViewContext ViewContext { get; set; }

        public CustomTagHelper(IHtmlHelper htmlHelper)
        {
            html = htmlHelper;
        }
        public override async Task ProcessAsync(TagHelperContext context, TagHelperOutput output)
        {
            //Contextualize the html helper
            (html as IViewContextAware).Contextualize(ViewContext);

            var content = await html.PartialAsync("~/Views/path/to/TemplateName.cshtml", DataModel.Model);
            output.Content.SetHtmlContent(content);
        }
    }

提供的IHtmlHelper实例尚未准备好使用,需要对其进行上下文化,因此(html格式为IViewContextAware).Contextualize(ViewContext);声明.

然后可以使用IHtmlHelper.Partial方法生成模板.

对于他对Facility for rendering a partial template from a tag helper的评论,功劳达到frankabbruzzese.