递归实现

      public long getClassIDByPartId(long partId)
        {
            DBConnect dbCon = new DBConnect(this);
            long iClassId, iProductId, iPartId, iParentPartId;
             
            string dsSql = "Select NodeID,ParentNodeID,Class,OrderIndex,PartId from DM_ProductTree order by Class Desc,ParentNodeID,OrderIndex;
            
            DataSet ds = dbCon.getDataSet(dsSql);
                        
            return getClassIDByNodeID(ds, 0, partId);
        }
        
        private long getClassIDByNodeID(DataSet ds, int fromNo, long varNodeID)
        {
            return getIDByNodeID(ds, fromNo, varNodeID, 0);
        }
       
        private long getProductIDByNodeID(DataSet ds, int fromNo, long varNodeID)
        {
            return getIDByNodeID(ds, fromNo, varNodeID, 1);
        }
         
        private long getIDByNodeID(DataSet ds, int fromNo, long varNodeID, int iFlg)
        {
            DataRow dr;
            for (i = fromNo; i < ds.Tables["tree"].Rows.Count; i++)
            {
                dr=dst.Tables["tree"].Rows[i];
                iNodeId = Convert.ToInt32(dr["NodeID"]);
                if (iNodeId == varNodeID){
                    iClass = Convert.ToInt32(dr["Class"]);
                    iParentNodeID = Convert.ToInt64(dr["ParentNodeID"]);
                    if (iClass == iFlg + 1)
                    {
                        return iParentNodeID;
                    }else{
                        return getClassIDByNodeID(ds, i, iParentNodeID);
                    }
                }
            }
        }