c# - Modify existing object with new partial JSON data using Json.NET -

consider below example program

var calendar = new calendar {     id = 42,     coffeeprovider = "espresso2000",     meetings = new[]     {         new meeting         {             location = "room1",             = datetimeoffset.parse("2014-01-01t00:00:00z"),             = datetimeoffset.parse("2014-01-01t01:00:00z")         },         new meeting         {             location = "room2",             = datetimeoffset.parse("2014-01-01t02:00:00z"),             = datetimeoffset.parse("2014-01-01t03:00:00z")         },     } };  var patch = @"{         'coffeeprovider': null,         'meetings': [             {                 'location': 'room3',                 'from': '2014-01-01t04:00:00z',                 'to': '2014-01-01t05:00:00z'             }         ]     }";  var patchedcalendar = patch(calendar, patch); 

the result of patch() method should equal calendar except changed patch. means; id unchanged, coffeeprovider set null , meetings contain single item located in room3.

1. how 1 create general patch() method work object (not example calendar object) deserializable json.net?

2. if (1) not feasible, restrictions make feasible , how implemented?

you want jsonserializer.populate() or static wrapper method jsonconvert.populateobject():

populates json values onto target object.

for instance, here updating instance of calendar class:

public static class testpopulate {     public static void test()     {         var calendar = new calendar         {             id = 42,             coffeeprovider = "espresso2000",             meetings = new[]             {                 new meeting                 {                     location = "room1",                     = datetimeoffset.parse("2014-01-01t00:00:00z"),                     = datetimeoffset.parse("2014-01-01t01:00:00z")                 },                 new meeting                 {                     location = "room2",                     = datetimeoffset.parse("2014-01-01t02:00:00z"),                     = datetimeoffset.parse("2014-01-01t03:00:00z")                 },             }         };          var patch = @"{     'coffeeprovider': null,     'meetings': [         {             'location': 'room3',             'from': '2014-01-01t04:00:00z',             'to': '2014-01-01t05:00:00z'         }     ] }";         patch(calendar, patch);          debug.writeline(jsonconvert.serializeobject(calendar, formatting.indented));     }      public static void patch<t>(t obj, string patch)     {         var serializer = new jsonserializer();         using (var reader = new stringreader(patch))         {             serializer.populate(reader, obj);         }     } } 

and debug output produced is:

{   "id": 42,   "coffeeprovider": null,   "meetings": [     {       "location": "room3",       "from": "2014-01-01t04:00:00+00:00",       "to": "2014-01-01t05:00:00+00:00"     }   ] } 

update

if want copy first, do:

    public static t copypatch<t>(t obj, string patch)     {         var serializer = new jsonserializer();          var json = jsonconvert.serializeobject(obj);         var copy = jsonconvert.deserializeobject<t>(json);          using (var reader = new stringreader(patch))         {             serializer.populate(reader, copy);         }          return copy;     }