分享一个递归无限级拼接Json的方法---ExtJs的TreePanel和TreeGrid均适用(Ef，Lambda,Linq,IQueryable,List)

话不多说，先上实体类，如果你不是codefirst,就把它当成数据表结构。

下面是底层BaseDal获取数据的方法（如果你没有Base类，直接写在你的DAL层和BLL层）

下面是BaseService的方法

下面方法用于拼接字符串

主体方法--

/// <summary>
        /// 得到****TreeGrid****的Json  ,后台用于管理页面
        /// </summary>
        public string GetAllLeftMenu4TreeGridJson()
        {
            StringBuilder allLeftMenuJsonStr = new StringBuilder();
            allLeftMenuJsonStr.Append("[");
 
            //int normal = Convert.ToInt32(Common.Enum.DelFlagEnum.Normal);//lambda表达式中不可以有类型转换
            //List<AdminLeftMenuInfo> adminLeftMenuInfos = GetEntitesQueryable(m => m.DelFlag == normal).ToList();
            List<AdminLeftMenuInfo> adminLeftMenuInfos = GetEntitesQueryable(m => m.DelFlag != -1).ToList(); //这样就是查询所有  软删除的也查询，未删除的也查询，便于前台进行管理
 
            foreach (var adminLeftMenuInfo in adminLeftMenuInfos)
            {
                if (adminLeftMenuInfo.ParentId == 0)           //如果该元素的父ID为0   则是顶级元素
                {
                    allLeftMenuJsonStr.Append("{");
                    allLeftMenuJsonStr.Append("\"text\":\" " + adminLeftMenuInfo.PageName + " \"  ");
                    allLeftMenuJsonStr.Append(",");
                    allLeftMenuJsonStr.Append("\"url\":\" " + adminLeftMenuInfo.PageUrl + " \"  ");
                    allLeftMenuJsonStr.Append(",");
                    allLeftMenuJsonStr.Append("\"delFlag\":\" " + adminLeftMenuInfo.DelFlag + " \"  ");
                    allLeftMenuJsonStr.Append(",");
                    allLeftMenuJsonStr.Append("\"Id\":\" " + adminLeftMenuInfo.Id + " \"  ");
                    allLeftMenuJsonStr.Append(",");
                    allLeftMenuJsonStr.Append("\"iconCls\":\"task-folder\"");
                    allLeftMenuJsonStr.Append(",");
                    allLeftMenuJsonStr.Append("\"expanded\":true");
 
                    List<AdminLeftMenuInfo> childrens = adminLeftMenuInfos.Where(m => m.ParentId == adminLeftMenuInfo.Id).ToList();
                    if (childrens.Count != 0) //如果他还有儿子---拼接儿子
                    {
                        allLeftMenuJsonStr.Append(",");
                        allLeftMenuJsonStr.Append("\"children\":");
                        DoAppendChildJson4TreeGrid(childrens, allLeftMenuJsonStr, adminLeftMenuInfos);
 
                    }
 
                    allLeftMenuJsonStr.Append("},");
 
                }
            }
            allLeftMenuJsonStr.Remove(allLeftMenuJsonStr.Length - 1, 1);
            allLeftMenuJsonStr.Append("]");
            return allLeftMenuJsonStr.ToString();
        }
 
        private void DoAppendChildJson4TreeGrid(List<AdminLeftMenuInfo> childrens, StringBuilder allLeftMenuJsonStr, List<AdminLeftMenuInfo> adminLeftMenuInfos)
        {
            allLeftMenuJsonStr.Append("[");
            foreach (var children in childrens)
            {
                //判断children是否还有儿子，如果有为folder,如果没有儿子就是leaf,
                //并且checked=false;
                //   var son = GetEntitesQueryable(m => m.ParentId == children.Id);
                List<AdminLeftMenuInfo> son = adminLeftMenuInfos.Where(m => m.ParentId == children.Id).ToList();
                if (son.Count == 0)  //没有儿子了 那么他就是叶子
                {
                    allLeftMenuJsonStr.Append("{");
                    allLeftMenuJsonStr.Append("\"text\":\"" + children.PageName + "\"");
                    allLeftMenuJsonStr.Append(",");
                    allLeftMenuJsonStr.Append("\"leaf\":true");
                    allLeftMenuJsonStr.Append(",");
                    allLeftMenuJsonStr.Append("\"delFlag\":\" " + children.DelFlag + " \"  ");
                    allLeftMenuJsonStr.Append(",");
                    allLeftMenuJsonStr.Append("\"iconCls\":\"task\"");
                    allLeftMenuJsonStr.Append(",");
                    allLeftMenuJsonStr.Append("\"Id\":\" " + children.Id + " \"  ");
                    allLeftMenuJsonStr.Append(",");
                    allLeftMenuJsonStr.Append("\"url\":\" " + children.PageUrl + " \"  ");
                    allLeftMenuJsonStr.Append("},");
                }
                else//有儿子 那么他就是文件夹
                {
                    allLeftMenuJsonStr.Append("{");
                    allLeftMenuJsonStr.Append("\"text\":\"" + children.PageName + "\"");
                    allLeftMenuJsonStr.Append(",");
                    allLeftMenuJsonStr.Append("\"iconCls\":\"task-folder\"");
                    allLeftMenuJsonStr.Append(",");
                    allLeftMenuJsonStr.Append("\"expanded\":true");
                    allLeftMenuJsonStr.Append(",");
                    allLeftMenuJsonStr.Append("\"url\":\" " + children.PageUrl + " \"  ");
                    allLeftMenuJsonStr.Append(",");
                    allLeftMenuJsonStr.Append("\"delFlag\":\" " + children.DelFlag + " \"  ");
                    allLeftMenuJsonStr.Append(",");
                    allLeftMenuJsonStr.Append("\"Id\":\" " + children.Id + " \"  ");
                    allLeftMenuJsonStr.Append(",");
                    allLeftMenuJsonStr.Append("\"children\":");
                    DoAppendChildJson4TreeGrid(son, allLeftMenuJsonStr,adminLeftMenuInfos);
                    allLeftMenuJsonStr.Append("},");
                }
 
            }
            allLeftMenuJsonStr.Remove(allLeftMenuJsonStr.Length - 1, 1);
            allLeftMenuJsonStr.Append("]");
        }