c# List列表数据转换成树形结构

把List列表结构 转换成树形结构

 /// <summary>
    /// 构造树形Json
    /// </summary>
    public static class TreeJson
    {

        /// <summary>
        /// 转换树Json
        /// </summary>
        /// <param name="list">数据源</param>
        /// <param name="parentId">父节点</param>
        /// <returns></returns>
        public static string ZTreeJson(this List<TreeEntity> list, string parentId = null)   //GetDepartmentTree等方法会给parentId赋值的是null，所以这里的parentId不能写""
        {
            StringBuilder strJson = new StringBuilder();
            List<TreeEntity> item = list.FindAll(t => t.parentId == parentId);
            strJson.Append("[");
            if (item.Count > 0)
            {
                foreach (TreeEntity entity in item)
                {
                    strJson.Append("{");
                    strJson.Append("\"id\":\"" + entity.id + "\",");
                    if (!string.IsNullOrEmpty(entity.text))
                    {
                        strJson.Append("\"name\":\"" + entity.text.Replace("&nbsp;", "") + "\",");
                    }
                    if (!string.IsNullOrEmpty(entity.Attribute))
                    {
                        strJson.Append("\"" + entity.Attribute + "\":\"" + entity.AttributeValue + "\",");
                    }
                    if (!string.IsNullOrEmpty(entity.AttributeA))
                    {
                        strJson.Append("\"" + entity.AttributeA + "\":\"" + entity.AttributeValueA + "\",");
                    }
                    if (!string.IsNullOrEmpty(entity.AttributeB))
                    {
                        strJson.Append("\"" + entity.AttributeB + "\":\"" + entity.AttributeValueB + "\",");
                    }
                    if (!string.IsNullOrEmpty(entity.AttributeC))
                    {
                        strJson.Append("\"" + entity.AttributeC + "\":\"" + entity.AttributeValueC + "\",");
                    }
                    if (entity.checkstate != null)
                    {
                        strJson.Append("\"checked\":" + entity.checkstate + ",");
                    }
                    strJson.Append("\"showcheck\":" + entity.showcheck.ToString().ToLower() + ",");
                    strJson.Append("\"open\":" + entity.isexpand.ToString().ToLower() + ",");
                    strJson.Append("\"isParent\":" + entity.hasChildren.ToString().ToLower() + ",");
                    strJson.Append("\"children\":" + ZTreeJson(list, entity.id) + "");
                    strJson.Append("},");
                }
                strJson = strJson.Remove(strJson.Length - 1, 1);
            }
            strJson.Append("]");
            return strJson.ToString();
        }

        /// <summary>
        /// 转换树Json
        /// </summary>
        /// <param name="list">数据源</param>
        /// <param name="ParentId">父节点</param>
        /// <returns></returns>
        public static string TreeToJson(this List<TreeEntity> list, string ParentId = null)   //GetDepartmentTree等方法会给parentId赋值的是null，所以这里的parentId不能写""
        {
            StringBuilder strJson = new StringBuilder();
            List<TreeEntity> item = list.FindAll(t => t.parentId == ParentId);
            strJson.Append("[");
            if (item.Count > 0)
            {
                foreach (TreeEntity entity in item)
                {
                    strJson.Append("{");
                    strJson.Append("\"id\":\"" + entity.id + "\",");
                    if (!string.IsNullOrEmpty(entity.text))
                    {
                        strJson.Append("\"text\":\"" + entity.text.Replace("&nbsp;", "") + "\",");
                    }
                    if (!string.IsNullOrEmpty(entity.value))
                    {
                        strJson.Append("\"value\":\"" + entity.value + "\",");
                    }

                    if (!string.IsNullOrEmpty(entity.Attribute))
                    {
                        strJson.Append("\"" + entity.Attribute + "\":\"" + entity.AttributeValue + "\",");
                    }
                    if (!string.IsNullOrEmpty(entity.AttributeA))
                    {
                        strJson.Append("\"" + entity.AttributeA + "\":\"" + entity.AttributeValueA + "\",");
                    }
                    if (entity.title != null && !string.IsNullOrEmpty(entity.title.Replace("&nbsp;", "")))
                    {
                        strJson.Append("\"title\":\"" + entity.title.Replace("&nbsp;", "") + "\",");
                    }
                    if (entity.img != null && !string.IsNullOrEmpty(entity.img.Replace("&nbsp;", "")))
                    {
                        strJson.Append("\"img\":\"" + entity.img.Replace("&nbsp;", "") + "\",");
                    }
                    if (entity.checkstate != null)
                    {
                        strJson.Append("\"checkstate\":" + entity.checkstate + ",");
                    }
                    //if (entity.parentId != null)
                    //{
                    //    strJson.Append("\"parentnodes\":\"" + entity.parentId + "\",");
                    //}
                    strJson.Append("\"parentnodes\":\"" + entity.parentId + "\",");
                    if (entity.Level != null)
                    {
                        strJson.Append("\"Level\":" + entity.Level + ",");
                    }
                    strJson.Append("\"showcheck\":" + entity.showcheck.ToString().ToLower() + ",");
                    strJson.Append("\"isexpand\":" + entity.isexpand.ToString().ToLower() + ",");
                    if (entity.complete == true)
                    {
                        strJson.Append("\"complete\":" + entity.complete.ToString().ToLower() + ",");
                    }
                    strJson.Append("\"hasChildren\":" + entity.hasChildren.ToString().ToLower() + ",");
                    strJson.Append("\"ChildNodes\":" + TreeToJson(list, entity.id) + "");
                    strJson.Append("},");
                }
                strJson = strJson.Remove(strJson.Length - 1, 1);
            }
            strJson.Append("]");
            return strJson.ToString();
        }
    }

原文地址：https://www.cnblogs.com/zhaops/p/10677718.html