csv импорт продукта таможенной таксономии не удается

Вот решение,

namespace Website1.Extensions
{
    public static class HtmlHelper
    {
        public static IHtmlContent Partial(this IHtmlHelper htmlHelper, string partialViewName, object model, string prefix)
        {
            var viewData = new ViewDataDictionary(htmlHelper.ViewData);
            var htmlPrefix = viewData.TemplateInfo.HtmlFieldPrefix;
            viewData.TemplateInfo.HtmlFieldPrefix += !Equals(htmlPrefix, string.Empty) ? $".{prefix}" : prefix;
            return htmlHelper.Partial(partialViewName, model, viewData);
        }

        public static Task<IHtmlContent> PartialAsync(this IHtmlHelper htmlHelper, string partialViewName, object model, string prefix)
        {
            var viewData = new ViewDataDictionary(htmlHelper.ViewData);
            var htmlPrefix = viewData.TemplateInfo.HtmlFieldPrefix;
            viewData.TemplateInfo.HtmlFieldPrefix += !Equals(htmlPrefix, string.Empty) ? $".{prefix}" : prefix;
            return htmlHelper.PartialAsync(partialViewName, model, viewData);
        }
    }
}

employee.cshtml

@using Website1.Extensions;
@model Employee
@Html.Partial("_contactInfo", Model.ContactInfo, nameof(Model.ContactInfo))

_contactInfo.cshtml

@using Website1.Extensions;
@model ContactInfo
@Html.Partial("_phoneInfo", Model.PhoneInfo, nameof(Model.PhoneInfo))

_phoneInfo.cshtml

@model PhoneInfo
<input asp-for="@Model.Contact1" />