onInit() {
    //隐藏分页信息
    this.paginationHide = true;
    //禁用延迟加载(必填)
    this.lazy = false;
    //树形结点的id字段(必填)
    this.rowKey = 'DepartmentId';//DepartmentId为表的主键id字段
    //父级id字段(必填)
    this.rowParentField = "ParentId";//ParentId为表的父级id字段
    //是否展开所有节点（默认会记录展开的节点）
    //this.defaultExpandAll=true;
    //默认展开的节点
    //this.expandRowKeys=["id值"]
}

onInit() {
      //设置treetable的唯一值字段(这个字段的值在表里面必须是唯一的)
      this.rowKey = 'Role_Id'; //Role_Id换为表的主键字段
},
/***加载后台数据***/
loadTreeChildren(tree, treeNode, resolve) {
    //加载子节点
    //Role_Id换为表的主键字段
    let url = `api/表名/getTreeTableChildrenData?roleId=${tree.Role_Id}`;
    this.http.post(url, {}).then((result) => {
       resolve(result.rows);
    });
}

/********************************后台代码**************************************/
//后台代码见：Sys_RoleController.cs文件(Sys_RoleController改为你当前表的Controller)
 public partial class Sys_RoleController
 {
    private readonly ISys_RoleService _service;//访问业务代码
    private readonly ISys_RoleRepository _repository;
    private readonly IHttpContextAccessor _httpContextAccessor;

    [ActivatorUtilitiesConstructor]
    public Sys_RoleController(
        ISys_RoleService service,
        ISys_RoleRepository repository,
        IHttpContextAccessor httpContextAccessor
    )
    : base(service)
    {
        _service = service;
        _repository = repository;
        _httpContextAccessor = httpContextAccessor;
    }

    /// <summary>
    /// treetable 获取子节点数据(2021.05.02)
    /// </summary>
    /// <param name="loadData"></param>
    /// <returns></returns>
    [ApiActionPermission(ActionPermissionOptions.Search)]
    [HttpPost, Route("GetPageData")]
    public override ActionResult GetPageData([FromBody] PageDataOptions loadData)
    {
        return GetTreeTableRootData(loadData).Result;
    }

    /// <summary>
    /// treetable 获取一级(根)节点数据
    /// </summary>
    /// <returns></returns>
    [HttpPost, Route("getTreeTableRootData")]
    [ApiActionPermission(ActionPermissionOptions.Search)]
    public async Task<ActionResult> GetTreeTableRootData([FromBody] PageDataOptions options)
    {
        //页面加载根节点数据条件x => x.ParentId == 0,自己根据需要设置
        var dbServiceId = UserContext.CurrentServiceId;
        var query = _repository.FindAsIQueryable(x => x.ParentId == 0 || x.Role_Id == 1);

        var queryChild = _repository.FindAsIQueryable(x => true);
        var rows = await query.TakeOrderByPage(options.Page, options.Rows)
            .OrderBy(x => x.Role_Id).Select(s => new
            {
                s.Role_Id,
                s.ParentId,
                s.RoleName,
                s.DeptName,
                s.Dept_Id,
                s.Enable,
                s.CreateDate,
                s.Creator,
                s.Modifier,
                s.ModifyDate,
                s.OrderNo,
                s.DatAuth,
                hasChildren = queryChild.Any(x => x.ParentId == s.Role_Id)
            }).ToListAsync();
        return JsonNormal(new { total = await query.CountAsync(), rows });
    }

    /// <summary>
    ///treetable 获取子节点数据
    /// </summary>
    /// <returns></returns>
    [HttpPost, Route("getTreeTableChildrenData")]
    [ApiActionPermission(ActionPermissionOptions.Search)]
    public async Task<ActionResult> GetTreeTableChildrenData(int roleId)
    {
        //点击节点时，加载子节点数据
        var roleRepository = Sys_RoleRepository.Instance.FindAsIQueryable(x => true);
        var query = roleRepository.Where(x => x.ParentId == roleId);
        if (AppSetting.UseDynamicShareDB)
        {
            query = query.Where(x => x.DbServiceId == UserContext.CurrentServiceId);
        }
        var rows = await query
            .Select(s => new
            {
                s.Role_Id,
                s.ParentId,
                s.RoleName,
                s.DeptName,
                s.Dept_Id,
                s.Enable,
                s.CreateDate,
                s.Creator,
                s.Modifier,
                s.ModifyDate,
                s.OrderNo,
                s.DatAuth,
                hasChildren = roleRepository.Any(x => x.ParentId == s.Role_Id)
            }).ToListAsync();
        return JsonNormal(new { rows });
    }
}