splitOn参数：用来指定列为分隔列，之前的列为前一对象，之后的列为后一对象。 lookup 用来保存中间处理结果，可以理解为将结果归组出Group对象，并为其RightsList添加内容， 注意：lookup中添加的是临时定义的Group对象，并在循环中将此对象从lookup中取出，为其RightsList添加Rights

class Rights{    public string ID{
     get;set;}    public string Name{ get;set;} }

class Group{    public string ID{
     get;set;}    public string Name{ get;set;} public List
    
      RightsList{ get;set;} }
    

CREATE TABLE `t_group_right` (  `rightId` varchar(50) NOT NULL, `groupId` varchar(50) NOT NULL, KEY `FK_group_rights_id` (`rightId`), KEY `FK_rights_group_id` (`groupId`), CONSTRAINT `FK_group_rights_id` FOREIGN KEY (`rightId`) REFERENCES `t_rights` (`id`), CONSTRAINT `FK_rights_group_id` FOREIGN KEY (`groupId`) REFERENCES `t_group` (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8;

查询角色列表 public List
    
      GetAll()        {            string sql = "SELECT a.*,c.* FROM t_group  a left join t_group_right b on a.id = b.groupid left join t_rights c on c.id=b.rightid ";            using (MySqlConnection conn = DapperFactory.CrateMySqlConnection())            {                var lookup = new Dictionary
     
      ();                var list = conn.Query
      
       (sql, (g, r) => { Group tmp; if (!lookup.TryGetValue(g.ID, out tmp)) { tmp = g; lookup.Add(g.ID, tmp); } tmp.RightsList.Add(r); return g; } , splitOn: "id").ToList(); return lookup.Values.ToList(); } }
      
     
    

Operator对象

class Operator{    public string ID{
     get;set;}    public string Name{ get;set;} [NoWrite] public List
    
      GroupList { get; set; } [NoWrite] public List
     
       RightsList { get; set; } }
     
    

查询一个Operator对象

public Operator Get(string id)        {            using (MySqlConnection conn = DapperFactory.CrateMySqlConnection())            {                string sql = "SELECT a.*,c.*,e.* FROM t_operator a left join t_operator_group b on a.id = b.operatorid left join t_group c on c.id=b.groupid " +                        "left join t_operator_rights d on a.id = d.operatorid left join t_rights e on e.id = d.rightid where a.id=@id";                Operator lookup = null;                conn.Query
    
     (sql, (o, g, r) => { if (lookup == null) { lookup = o; } Group tmp = lookup.GroupList.Find(f => f.ID == g.ID); if (tmp == null) { tmp = g; lookup.GroupList.Add(tmp); } tmp.RightsList.Add(r); lookup.RightsList.Add(r); return o; }, param: new { id = id }, splitOn: "id"); return lookup; } }
    

获取Operator列表： public List
    
      GetAll()        {            using (MySqlConnection conn = DapperFactory.CrateMySqlConnection())            {                string sql = "SELECT a.*,c.*,e.* FROM t_operator a left join t_operator_group b on a.id = b.operatorid left join t_group c on c.id=b.groupid " +                        "left join t_operator_rights d on a.id = d.operatorid left join t_rights e on e.id = d.rightid";                var lookup = new Dictionary
     
      (); conn.Query
      
       (sql, (o, g, r) => { Operator tmp; if (!lookup.TryGetValue(o.ID,out tmp)) { tmp = o; lookup.Add(o.ID,tmp); } Group tmpG = tmp.GroupList.Find(f => f.ID == g.ID); if (tmpG == null) { tmpG = g; tmp.GroupList.Add(tmpG); } //角色权限列表 Rights tmpR = tmpG.RightsList.Find(f => f.ID == r.ID); if (tmpR == null) { tmpG.RightsList.Add(r); } //用户权限列表 tmpR = tmp.RightsList.Find(f => f.ID == r.ID); if (tmpR == null) { tmp.RightsList.Add(r); } return o; }, splitOn: "id"); return lookup.Values.ToList(); } }