//َAgent Entity

    public class Agent:BaseEntity,ISoftDeleteModel
    {
        public int AgentId { get; set; }
        [MaxLength(300, ErrorMessage = "{0} حداکثر می‌تواند شامل {1} کاراکتر باشد")]
        public string Title { get; set; }
        public int Sort { get; set; }
        public bool IsDisplayed { get; set; } = true;
        [ForeignKey("Parent")]
        public int? ParentID { get; set; }
        public bool IsDeleted { get; set; }
        [InverseProperty("AgentSend")]
        public ICollection<LetterAgent> LetterAgentsSend { get; set; }
        [InverseProperty("AgentReceive")]
        public ICollection<LetterAgent> LetterAgentsReceive { get; set; }
        public ICollection<UserAgent> UserAgents { get; set; }
        public Agent? Parent { get; set; }
        public ICollection<Agent>? SubGroups { get; set; }

    }

            //SelfReferential
            modelBuilder.Entity<Agent>(entity =>
            {
                entity.HasIndex(e => e.ParentID);

                entity.HasOne(d => d.Parent)
                    .WithMany(p => p.SubGroups)
                    .HasForeignKey(d => d.ParentID);
            });

        <DntTreeView
            TRecord="AgentDTO"
            Items="Comments"
            ChildrenSelector="m => m.SubGroups"
            style="list-style: none;"
            ChildrenHtmlAttributes="ChildrenHtmlAttributes">
            <ItemTemplate Context="record">
                <div class="card mb-1">
                    <div class="card-body">
                        <span>@record.Title</span>
                    </div>
                </div>
            </ItemTemplate>
            <EmptyContentTemplate>
                <div class="alert alert-warning">
                    There is no item to display!
                </div>
            </EmptyContentTemplate>
        </DntTreeView>