ASP.NET MVC AJAX POST 500 Internenal Server Error - asp.net

Question

I want to update the row but when I click the update buttton return json result that message "500 Internenal Server Error". I don't find the problem. Can you check the code?
[HttpPost]
public JsonResult UpdateInStock(int stokID, int amount, int uCost, int sumCost, string detail, string unit)
{
var model = db.tbl_InStock.Where(x => x.stockInID == stokID).FirstOrDefault();
model.stockInAmount = amount;
model.stockInCost = uCost;
model.stockInSum = sumCost;
model.stockInDetail = detail;
model.stockInUnit = unit;
//db.SaveChanges();
return Json(new { result = "Redirect", url = Url.Action("Gelen", "Anasayfa") });
}
I want to update the row but when I click the update buttton return json result that message "500 Internenal Server Error". I don't find the problem. Can you check the code?
//Jquery Code
$("#uptInStock").click(function () {
var no = $.trim($("#stokInIDD").val());
var miktar = $.trim($("#amountt").val());
var fiyat = $.trim($("#unitCostt").val());
var toplam = $.trim($("#sumCostt").val());
var detay = $.trim($("#detaill").val());
var birim = $.trim($("#birimm option:selected").text());
var obj = { stokID: no, amount: miktar, uCost: fiyat, sumCost: toplam, detail: detay, unit: birim };
$.ajax({
type: "POST",
url: 'UpdateInStock',
crossDomain: true,
data: JSON.stringify(obj),
contentType: 'application/json;charset=utf-8"',
dataType: 'json',
success: function (response) {
if (response.result == 'Redirect')
window.location = response.url;
alert("Suc");
},
error: function (XMLHttpRequest, textStatus, errorThrown) {
alert(errorThrown);
}
});
});
//Html Code
#using (Html.BeginForm("UpdateInStock", "Anasayfa", FormMethod.Post))
{
<div class="modal-header">
<h5 class="modal-title" id="exampleModalLabel">Gelen Ürün - Güncelle</h5>
</div>
<div class="modal-body">
<input type="hidden" class="form-control" id="proIDD" />
<input type="hidden" class="form-control" id="stokInIDD" />
<div class="form-group">
<label class="sr-only mb-4" for="inlineFormInputGroup">Miktar</label>
<div class="proUnit2 input-group mb-4">
<div class="input-group-prepend">
<div class="input-group-text">Miktar</div>
</div>
<input type="text" class="form-control" id="amountt" />
</div>
</div>
<div class="form-group">
<select class="form-control mb-4" id="birimm" name="birim">
<option value="0">Birim Seçiniz</option>
<option value="1">Adet</option>
<option value="2">Bidon</option>
<option value="3">Koli</option>
<option value="4">Paket</option>
</select>
</div>
<div class="form-group">
<label class="sr-only mb-4" for="inlineFormInputGroup">Birim Fiyatı</label>
<div class="proUnit input-group mb-4">
<div class="input-group-prepend">
<div class="input-group-text"><i class="fa fa-try" aria-hidden="true"></i></div>
</div>
<input type="text" class="form-control" id="unitCostt" placeholder="Birim fiyatı" />
</div>
</div>
<div class="form-group">
<label class="sr-only mb-4" for="inlineFormInputGroup">Toplam Fiyatı</label>
<div class="proUnit input-group mb-4">
<div class="input-group-prepend">
<div class="input-group-text"><i class="fa fa-try" aria-hidden="true"></i></div>
</div>
<input type="text" class="form-control" id="sumCostt" placeholder="Toplam fiyatı" />
</div>
</div>
<div class="form-group">
<input type="text" class="form-control" id="detaill" placeholder="Açıklama" />
</div>
</div>
<div class="modal-footer">
<button type="button" class="btn btn-secondary btn-sm" data-dismiss="modal">Vazgeç</button>
<button id="uptInStock" type="button" class="btn btn-primary btn-sm">Kaydet</button>
</div>
}

Answer 1

Please try your url with Controller,ActionAnd Area if necessary. Below is some sample url you can try.
url:"/Area/Controller/ActionName" (in your case UpdateInStock is your action name)
url:"/Controller/ActionName"
Or you can use #Url.Action with razor syntax.
url:"#Url.Action("ActionName", "Controller")"

Answer 2

I solved the problem. The problem was with the numbers with commas.
var fiyat = $.trim($("#unitCostt").val());
var toplam = $.trim($("#sumCostt").val());
These fields should be converted to float values.
var fiyat = parseFloat($.trim($("#unitCostt").val()));
var toplam = parseFloat($.trim($("#sumCostt").val()));