DataTable convert to JSON Format

Question

I have C# DataTable  in the following format: 

ID    |  ParetCode|ChildCode| AttName | AttCode|
-------------------------------------------------
01    | 01        | 001    |  att1   | 3    |
02    | 01        | 001    |  att2   | 456  |
03    | 01        | 002    |  att1   | 87   |
04    | 01        | 002    |  att0   | 65   |
05    | 02        | 054    |  att1   | 54654|

How can I convert that into a Json object as follows?

[
    {"id":"01","ParentCode":"01","ChildCode":001
                                 {"AttName":"att1",                                  "AttCode":3,
                                  "AttName":"att2",                                   "AttCode":456,
                                   },                                  "ChildCode":002
                                             {
                                             "AttName":"att1",                                                                               "AttCode":87,
                                                                                          "AttName":"att0",                                                                                          "AttCode":65
                                             }
    {"id":"05","ParentCode":"02","ChildCode":054
                                                {"AttName":"att1",
                                                 "AttCode":"54654"
                                                }
    }
]