EF Core子表多个外键关连同一主表设置方法

 当子表的多个外键关连同一主表时，ef core模型应该如何配置呢？

例：记录一条销售单信息，需要保存销售员、和制单人（记录的操作人），而这两个字段都需要指向user表。

销售单表（子表）b01_so模型类如下：

using system;
using system.collections.generic;
using system.linq;
using system.threading.tasks;
using system.componentmodel.dataannotations;

namespace test.models
{
    public class b01_so
    {
       [key]
        public int id { get; set; }

        [display(name ="销售单号")]
        [stringlength(50)]
        [required]
        public string sonum { get; set; }

        [display(name = "单据编号")]
        [stringlength(50)]        
        public string tknum { get; set; }


        [display(name = "交期")]
        [required]
        public datetime dtime { get; set; }

        [display(name = "产品描述")]
        [stringlength(200)]
        [required]
        public string description { get; set; }


        [display(name = "销售员")]
        public int? saleid { get; set; }
        [display(name = "销售员")]
        public user sales { get; set; }


        [display(name = "制单人")]        
        public int? userid { get; set; }
        [display(name = "制单人")]
        public user user { get; set; }

    }
}

user表（主表）模型类如下：

using system;
using system.collections.generic;
using system.linq;
using system.web;
using system.componentmodel.dataannotations;
using system.componentmodel.dataannotations.schema;

namespace test.models
{
    public class user
    {
        [key]
        public int id { get; set; }

        [display(name = "用户名")]
        [stringlength(50)]
        [required]
        public string name { get; set; }

        [display(name = "邮箱")]
        [stringlength(100)]
        [required]
        public string email { get; set; }

        [display(name = "密码")]
        [stringlength(50)]
        [required]
        public string password { get; set; }

        [display(name = "是否启用")]
        [required]
        public bool enabled { get; set; }

        [display(name = "性别")]
        [stringlength(10)]
        [required]
        public string gender { get; set; }

        [display(name = "中文名")]
        [stringlength(100)]
        public string chinesename { get; set; }

        [display(name = "英文名")]
        [stringlength(100)]
        public string englishname { get; set; }

        [display(name = "照片")]
        [stringlength(200)]
        public string photo { get; set; }

        [display(name = "qq")]
        [stringlength(50)]
        public string qq { get; set; }

        [display(name = "公司邮箱")]
        [stringlength(100)]
        public string companyemail { get; set; }

        [display(name = "工作电话")]
        [stringlength(50)]
        public string officephone { get; set; }

        [display(name = "分机号")]
        [stringlength(50)]
        public string officephoneext { get; set; }

        [display(name = "家庭电话")]
        [stringlength(50)]
        public string homephone { get; set; }

        [display(name = "手机号")]
        [stringlength(50)]
        public string cellphone { get; set; }

        [display(name = "地址")]
        [stringlength(500)]
        public string address { get; set; }

        [display(name = "备注")]
        [stringlength(500)]
        public string remark { get; set; }

        [display(name = "身份证")]
        [stringlength(50)]
        public string identitycard { get; set; }


        [display(name = "生日")]
        public datetime? birthday { get; set; }
        [display(name = "任职时间")]
        public datetime? takeofficetime { get; set; }
        [display(name = "上次登录时间")]
        public datetime? lastlogintime { get; set; }
        [display(name = "创建时间")]
        public datetime? createtime { get; set; }
        
        public icollection<b01_so> salseb01_sos { get; set; }
        public icollection<b01_so> userb01_sos { get; set; }

    }

    
}

fluent  api 配置：

using system;
using system.collections.generic;
using system.linq;
using system.web;
using microsoft.entityframeworkcore;
using microsoft.extensions.logging;

namespace testcore.models
{
    public class testcorecontext : dbcontext
    {
        #region 启用控制台日志 ef core
        public static readonly iloggerfactory myloggerfactory = loggerfactory.create(builder => { builder.addconsole(); });
        protected override void onconfiguring(dbcontextoptionsbuilder optionsbuilder)
            => optionsbuilder
                .useloggerfactory(myloggerfactory);
        #endregion

        public testcorecontext(dbcontextoptions<testcorecontext> options) : base(options)
        {
        }
        
        public dbset<user> users { get; set; }        
        public dbset<b01_so> b01_so { get; set; }

        protected override void onmodelcreating(modelbuilder modelbuilder)
        {
            base.onmodelcreating(modelbuilder);

            modelbuilder.entity<b01_so>()
                .hasone(u => u.user)
                .withmany(u => u.userb01_sos)
                .hasforeignkey(s => s.userid)
                .ondelete(deletebehavior.restrict)
                .isrequired();
            modelbuilder.entity<b01_so>()
                .hasone(u => u.sales)
                .withmany(u => u.salseb01_sos)
                .hasforeignkey(s => s.saleid)
                .ondelete(deletebehavior.restrict)
                .isrequired();
            
        }        
    }
}