c# - How to convert datatable record into child custom Class -

i have 2 classes namely:

public class parent {     public int id { get; set; }     public int { get; set; }     public int b { get; set; } }  public class child : parent {     public int c { get; set; }     public int d { get; set; } } 

and have 2 datatables following records

datatable (parent table) id         b 1      2     4 2      3     6 3      8     7 4      5     9  datatable ii (child table) parentid     c       d 2            4       10 4            9       7 

if want convert parent datatable parent objects user following code:

ilist<parent> items = dt.asenumerable().select(row =>      new parent         {             id = row.field<int>("id"),             = row.field<int>("a"),             b = row.field<int>("b"),         }).tolist(); 

obviously parent objects id of 2 , 4 has created child objects have no idea how that.

please me on this. in advance.

you wrote:

obviously parent objects id of 2 , 4 has created child objects

that not obvious. according layout, table ii have 2 rows same parentid, in example mean 2 people living together, while property , b address , telephone number while property c , d might mean birthday , favourite sport: 2 people living same address , telephone number , different birthday , different favourite sport.

if wanted express in database there 1 child parent id 2 , 1 child parent id 4, database wouldn't match first normal database form , different table layout prevent 2 people living better.

having said that, guess want following:

create list children table ii , add parents don't have child in table ii. properties , b children should taken table id equals parentid.

• create dictionary parents i
• create sequence children ii, use dictionary find values properties , b
• take parents don't have child in ii
• concat children , last parent list

.

var parentdictionary = asenumerable().todictionary(p => p.id); ienumerable<parent> children = ii.asenumerable()     .where( c => parentdictionary.keys.contains(c.parentid))     .select(c => new child()         {             = parentdictionary[c.id].a,             b = parentdictionary[c.id].b,             c = c.c,             d = c.d          })     .cast<parent>();  ienumerable<parent> parentswithoutchildren = i.asenumerable()     .where(p => !ii.asenumerable().contains(p.id));  ienumerable<parent> requestedpersons = parentswithoutchildren     .concat(children);