在ASP.NET核心MVC上绘制外键CSVHELPER

Question

我有几个外国关键领域，CountyID，Subcountyid，Wardid和ViryatiD，它们与县，子县等链接。桌子很明显。现在，我已经为null进行了头部服务，丢失fieldfound = null如何使用转换链接以链接外键条目？目前，有了以下代码，外键条目没有映射，我的相关表最终将插入新值。

List < Farmer > farmers = new List < Farmer > ();

#
region Read CSV

var path = $ "{Directory.GetCurrentDirectory()}{@"\
wwwroot\ files "}" + "\\" + fileName;
var conf = new CsvConfiguration(CultureInfo.InvariantCulture) {
  HeaderValidated = null,
    MissingFieldFound = null,
};
using(var reader = new StreamReader(path))
using(var csv = new CsvReader(reader, conf)) {
  csv.Read();
  csv.ReadHeader();
  while (csv.Read()) {
    var farmer = csv.GetRecord < Farmer > ();
    farmers.Add(farmer);
  }
}
return farmers;

农民课看起来像这样。

public class Farmer
{
    public int Id { get; set; }

    public string FirstName { get; set; }

    public string LastName { get; set; }

    public string PhoneNumber { get; set; }

    public int? VarietyId { get; set; }

    public virtual Variety Variety { get; set; }

    public int? CountyId { get; set; }

    public virtual County County { get; set; }

    public int? SubCountyId { get; set; }

    public virtual SubCounty SubCounty { get; set; }

    public int? WardId { get; set; }

    public virtual Ward Ward { get; set; }

    public int? TownId { get; set; }

    public virtual Town Town { get; set; }
}