linq2db问题 员工有一个技能列表-Skillidfks。 许多员工可以拥有一种技能，一名员工可以具有多种技能。员工和技能由EmployeeSkill实体链接，这也表明该技能的知识水平。 我能否以某种方式将EmployeeSkill实体添加到Skillidfks列表中，以便在保存员工时也保存其EmployeeSkill？

[Table(Schema="public",Name="employee")]
    public partial class Employee
    {
        [Column("id"),PrimaryKey,Identity] public long     Id                   { get; set; } // bigint
        [Column("surname"),NotNull              ] public string   Surname              { get; set; } // text
        [Column("name"),NotNull              ] public string   Name                 { get; set; } // text
        [Column("patronymic"),Nullable          ] public string   Patronymic           { get; set; } // text
        [Column("phone"),NotNull              ] public string   Phone                { get; set; } // text
        [Column("address"),NotNull              ] public string   Address              { get; set; } // text
        [Column("passport_number_series"),NotNull              ] public string   PassportNumberSeries { get; set; } // text
        [Column("passport_info_whom"),NotNull              ] public string   PassportInfoWhom     { get; set; } // text
        [Column("passport_info_when"),NotNull              ] public DateTime PassportInfoWhen     { get; set; } // timestamp (6) without time zone
        [Column("department_id"),Nullable          ] public long?    DepartmentId         { get; set; } // bigint
        [Column("position_id"),Nullable          ] public long?    PositionId           { get; set; } // bigint


        [Association(ThisKey="DepartmentId",OtherKey="Id",CanBeNull=true,Relationship=Relationship.ManyToOne,KeyName="employee_fk_1",BackReferenceName="Employeefks")]
        public Department Department { get; set; }

        [Association(ThisKey="PositionId",KeyName="employee_fk_2",BackReferenceName="Employeefks")]
        public Position Position { get; set; }

        [Association(ThisKey="Id",OtherKey="EmployeeId",Relationship=Relationship.OneToMany,IsBackReference=true)]
        public IEnumerable<EmployeeSkill> Skillidfks { get; set; }

    }

[Table(Schema="public",Name="employee_skill")]
    public partial class EmployeeSkill
    {
        [Column("employee_id"),PrimaryKey(1),NotNull] public long  EmployeeId { get; set; } // bigint
        [Column("skill_id"),PrimaryKey(2),NotNull] public long  SkillId    { get; set; } // bigint
        [Column("level"),NotNull] public short Level      { get; set; } // smallint

        [Association(ThisKey="EmployeeId",CanBeNull=false,KeyName="employee_skill_employee_id_fk",BackReferenceName="Skillidfks")]
        public Employee Employee { get; set; }

        [Association(ThisKey="SkillId",KeyName="employee_skill_skill_id_fk",BackReferenceName="Employeeidfks")]
        public Skill Skill { get; set; }
    }

[Table(Schema="public",Name="skill")]
    public partial class Skill
    {
        [Column("id"),Identity] public long   Id   { get; set; } // bigint
        [Column("name"),NotNull             ] public string Name { get; set; } // text
        [Association(ThisKey="Id",OtherKey="SkillId",IsBackReference=true)]
        public IEnumerable<EmployeeSkill> Employeeidfks { get; set; }
    }

我尝试了

Employee.Skillidfks.Append(new EmployeeSkill
                        {
                            Employee = Employee,EmployeeId = Employee.Id,Level = short.Parse(skillLevelChooserViewModel.Level),Skill = Parent.SkillsViewModel.SelectedSkill,SkillId = Parent.SkillsViewModel.SelectedSkill.Id
                        });

但不起作用