Accepting a List from Javascript Ajax Post to C# Method

Question

I would like to know how to pass a list of valid Targets into the method PassThings() from Javascript to C#. For Example something like this coming from a Javascript $.ajax post.

{
    "OverheadID": "31l",
    "ValuationClassID": 1,
    "InventoryElementID": 1,
    "Target_A_LC": 0,
    "Target_A_QTY": 0,
    "Target_B_LC": null,
    "Target_B_QTY": null,
    "TargetDescription": null
  },
  {
    "OverheadID": "31l",
    "ValuationClassID": 1,
    "InventoryElementID": 2,
    "Target_A_LC": 0,
    "Target_A_QTY": 0,
    "Target_B_LC": null,
    "Target_B_QTY": null,
    "TargetDescription": null
  },
  {
    "OverheadID": "31l",
    "ValuationClassID": 1,
    "InventoryElementID": 3,
    "Target_A_LC": 0,
    "Target_A_QTY": 0,
    "Target_B_LC": null,
    "Target_B_QTY": null,
    "LopTargetDescription": null
  },
  {
    "OverheadID": "31l",
    "ValuationClassID": 2,
    "InventoryElementID": 1,
    "Target_A_LC": 0,
    "Target_A_QTY": 0,
    "Target_B_LC": null,
    "Target_B_QTY": null,
    "TargetDescription": null
  }

I have been unable to get any kind of list to work from my Javascript $.ajax post to the C# method PassThings().

I only have been able to hard code the variable OneOfNine which represents a single valid Target in JSON format.

This was to confirm that the Javascript will send a valid syntax and my JsonConvert.DeserializeObject<Target>(OneOfNine) would function.

public class Target{       
    public virtual string OverheadID { get; set; } //not a true Fkey
    public int ValuationClassID { get; set; } //not a true Fkey     
    public int InventoryElementID { get; set; } //not a true Fkey
    public decimal? Target_A_LC { get; set; } //LOP Target A Local Currency
    public decimal? Target_A_QTY { get; set; } //LOP Target A Qty
    public decimal? Target_B_LC { get; set; } //Target B Local Currency
    public decimal? Target_B_QTY { get; set; } //LOP Target B Qty
    public string TargetDescription { get; set; } //optional text reference 
}   

public IActionResult PassThings()
{ 

    var OneOfNine = "{ \"OverheadID\": \"ASASAS\", \"ValuationClassID\": 2, \"InventoryElementID\": 3, \"Target_A_LC\": 0, \"Target_A_QTY\": 0, \"Target_B_LC\": 0, \"Target_B_QTY\": 0, \"TargetDescription\": \"na\" }";
    var deserial = JsonConvert.DeserializeObject<Target>(OneOfNine);

    var resource =
    new Target
    {
        OverheadID = deserial.OverheadID,
        ValuationClassID = deserial.ValuationClassID,
        InventoryElementID = deserial.InventoryElementID,
        Target_A_LC = deserial.Target_A_LC,
        Target_A_QTY = deserial.Target_A_QTY,
        Target_B_LC = deserial.Target_B_LC,
        Target_B_QTY = deserial.Target_B_QTY,
        TargetDescription = deserial.TargetDescription
    };

    return Ok(resource);
}

I tried setup like this

public IActionResult PassThings([FromBody]List<Target> things)

And my Javascript code in this format.

$.ajax({
    type: 'POST',
    //contentType: 'application/json; charset=utf-8',
    accepts: 'application/json', //mandatory activity
    contentType: 'application/json', //mandatory activity
    url: '/api/APILopTargets/PassThings',
    data: JSON.stringify(things)
});

try accepting it as an array instead of a List -- you can always convert it if you need to use List operations: `public IActionResult PassThings([FromBody]Target[] things)` — willman, Feb 18 '20 at 22:02
Does this answer your question? [Passing A List Of Objects Into An MVC Controller Method Using jQuery Ajax](https://stackoverflow.com/questions/13242414/passing-a-list-of-objects-into-an-mvc-controller-method-using-jquery-ajax) — Hamed Moghadasi, Feb 18 '20 at 22:06
replace `[FromBody]List` with `[FromBody]dynamic` and debug. When you will see the format of incoming data you will understand what's wrong. P.S. You may want to remove `virtual` from OverheadID property... — Anonymous, Feb 18 '20 at 22:16
Also, when you have arguments like `dynamic things` you can try to cast dynamic to List explicitly. If something is wrong, you'll get more meaningful exception. `var items = things.Cast>()` or `var items = things.Cast()` — Anonymous, Feb 18 '20 at 22:18
Please ensure that the data begins with "[" and ends with "]" to make it a list within the JSON file. And then use [FromBody] List things again. — Mosia Thabo, Feb 18 '20 at 22:26

score 2 · Accepted Answer · answered Feb 19 '20 at 08:34

If you would like url to be/api/APILopTargets/PassThings, the ApiController needs to be configured like

[Route("api/[controller]")]
[ApiController]
public class APILopTargetsController : ControllerBase
{
    [HttpPost("PassThings")]//add the attribute
    public IActionResult PassThings([FromBody]List<Target> things)
    {...}
}

JavaScript:

var things = [
      {
       "OverheadID": "31l",
       "ValuationClassID": 1,
       "InventoryElementID": 1,
       "Target_A_LC": 0,
       "Target_A_QTY": 0,
       "Target_B_LC": null,
       "Target_B_QTY": null,
       "TargetDescription": null
      },
      {...},
      ...
    ];

$.ajax({
        contentType: 'application/json; charset=utf-8',
        type: 'POST',
        url: '/api/APILopTargets/PassThings',
        data: JSON.stringify(things),
        success: function (result) {

        }
 });

Accepting a List from Javascript Ajax Post to C# Method

1 Answers1