我正在尝试将数据发布到ASP中的控制器。NET Core在控制器中接收null。
我无法将任何数据POST到端点。
在行动中

[HttpPost]
    public ActionResult AddEarningg([FromBody] ProgramAddDTO program)
    {
        //_ProgramAppService.AddEarning(program);

        ViewData["tenantlist"] = ListItems();
        return View();
    }

在 AJAX 代码中：

<script src="~/Common/Scripts/select2.min.js"></script>
<script>
   

    $(document).ready(function () {
     $("#SubProductCodeId").select2();
    $("#ProductId").select2();
    $("#ProductCodeId").select2();
    $("#ProductCodeId").select2();
    $("#CountryId").select2();
    $("#MerchantId").select2();
    $("#ChannelId").select2();
    $("#SegmentId").select2();
    $("#BtnSubmit").click(function () {
        var formdata = {};
        
        formdata.institutionId = $("#InstitutionId").val();
        formdata.programName = $("#ProgramName").val();
        formdata.productId = $("#ProductId").val();
        formdata.productCodeId = $("#ProductCodeId").val();
         formdata.subProductId= $("#SubProductId").val();
         formdata.TransactionTypeId= $("#TransactionTypeId").val();
         formdata.ChannelId= $("#ChannelId").val();
         formdata.SubProductCodeId= $("#SubProductCodeId").val();
         formdata.SpendToEarn= $("#SpendToEarn").val();
         formdata.EquivalnetPoint= $("#EquivalnetPoint").val();
         formdata.CountryId= $("#CountryId").val();
         formdata.MCCId= $("#MCCId").val();
         formdata.MerchantId= $("#MerchantId").val();
         formdata.SegmentId= $("#SegmentId").val();
         formdata.CapsMin= $("#CapsMin").val();
         formdata.CapsMax= $("#CapsMax").val();
        formdata.PointsExpiry = $("#PointsExpiry").val();
        var t = JSON.stringify(formdata)
        $.ajax({
            url: '/app/Program/AddEarningg',
            type: 'POST',
            contentType: "application/json; charset=utf-8",
            data: JSON.stringify({ 'program': formdata }),
        
            success: function () {
                alert("test");
            }
        });
    });
       

    });     
</script>

在DTO程序AddDTO类中

public class ProgramAddDTO
{
    //public int? ProgramTypeId { get; set; }

    public int InstitutionId { get; set; }

    public string ProgramName { get; set; }

    public List<int?> ProductId { get; set; }
    public List<int?> ProductCodeId { get; set; }

    public List<int?> SubProductId { get; set; }
    public List<int?> SubProductCodeId { get; set; }

    public List<int?> CountryId { get; set; }

    public int? TransactionTypeId { get; set; }

   
    public int EquivalnetPoint { get; set; }
   
    public int PointValue { get; set; }
    public List<int?> ChannelId { get; set; }
    public List<int?> MCCId { get; set; }
    public List<int?> MerchantId { get; set; }
    public List<int?> SegmentId { get; set; }

    public decimal CapsMin { get; set; }

    public decimal CapsMax { get; set; }

    public int? PointsExpiry { get; set; }

    public int SpendToEarn { set; get; }
}

当我向post方法传递一个复杂的JSON时，它总是显示null。
我使用的是select2 jquery库。