Is it possible to change from JSON object to JSON array in controller

Question

Im using SlickGrid and was tying to add data from grid to the DB when the user press the Enter key. It is sendig and JSON object (e.g. {"name":"value"}) and I need it as an array since im using type 'System.Collections.Generic.List'. Is its possible, in the controller , change it to a JSON array ? The data is obtained from the grid itself. Thanks in advance!

I've seen some similar situations but Im still gettint the error :

Newtonsoft.Json.JsonSerializationException: 'Cannot deserialize the current JSON object (e.g. {"name":"value"}) into type 'System.Collections.Generic.List`1[DAL.SlickGridTest]' because the type requires a JSON array (e.g. [1,2,3]) to deserialize correctly.

this is my action public ActionResult EditGridEnter(string mydata) and this is my jquery $.post

grid.onKeyDown.subscribe(function(e) {
  var keyPressed = event.keyCode || event.which;
  if (keyPressed == 13) {
    var myJSON = JSON.stringify(item);
    $.post("/SlickGridTest/EditGridEnter", $("input[name=mydata]").val(myJSON));
  }
});

This is what comes from item :

var idData = jsonResult[key].id + 1;
var item = { "id": idData, "t_nome": "", "t_prof": "", "t_data": "", "t_morada": "", "t_percCompleto": "" };

all data comes from the grid in slickgrid

This is how I deserialize the object:

var slcgrd= JsonConvert.DeserializeObject<List<SlickGridTest>>(mydata);

I expect to get values as an array (e.g. [1,2,3]) and im getting as object ( Object {id: 43, t_nome: "name name", t_prof: "prof", …} )

Your MVC action takes a string, so your question is missing information concerning ***how*** you are attempting to deserialize that string to your desired type, and what that type is. You also don't describe what you're sending (i.e. the value of `item` in the JS code) — spender, May 24 '19 at 09:52
`var array = Object.keys(item).map(function(key) { return [Number(key), item[key]]; });` as seen on this post: https://stackoverflow.com/questions/38824349/how-to-convert-an-object-to-an-array-of-key-value-pairs-in-javascript — GrafiCode, May 24 '19 at 09:54
or, if you only need an array of values (without preserving the object's keys) just use: `var array = Object.values(item);` — GrafiCode, May 24 '19 at 09:59
So is type `SlickGridTest` the same shape as that JS variable, `item`? — spender, May 24 '19 at 10:03
@GrafiCodeStudio ok, now is in an array! My question now is : can the controller recieve an array as argument? Im kinda fresh to ASP.NET and self-learning :c — daaavs, May 24 '19 at 10:06
@spender yes ! But the `SlickGridTest` is my DAL class, and `item` is where the data the user introduced in the grid goes. Then is passes and comes to the controller as JSON object ! But my `SlickGridTest` needs an array . ( if I get your question right) — daaavs, May 24 '19 at 10:09
uhm, there's no `list` data type in javascript, but a simple array like that is basically a list... hope asp.net likes it — GrafiCode, May 24 '19 at 10:09
@GrafiCodeStudio hum , the controller does not get the data ! it recieves `mydata Count = 0` :/ — daaavs, May 24 '19 at 10:19
Isn't it then as simple as wrapping the item up in an array? `var myJSON = JSON.stringify( [item] );` ? — spender, May 24 '19 at 11:47
... or deserializing a single object instead of a list? `var slcgrd= JsonConvert.DeserializeObject(mydata);` ? — spender, May 24 '19 at 11:49
@spender I've done deserializing a simple object instead of list! Didnt update yet because was at lunch break! But thanks! Even your first comment its pretty simple and more practice, since I dont need to change the controller! Put as answer so I can accept! and thanks a lot! — daaavs, May 24 '19 at 13:07

score 1 · Accepted Answer · answered May 24 '19 at 13:24

So, it appears you are trying to deserialize to a List<SlickGridTest>. When deserializing to a list, the deserializer expects to see a JSON array structure. As such you have two choices.

Either send an array with a single item:

var myJSON = JSON.stringify( [item] );

or change your controller deserialization to expect a single item instead:

var slcgrd= JsonConvert.DeserializeObject<SlickGridTest>(mydata);

Is it possible to change from JSON object to JSON array in controller

1 Answers1