I have a problem in project ASP core MVC

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C#

ASP.NET-Core

hi Every One nice to meet you Iam Happy for Register in this Site i have big problem for two week I Can not find solution for this error i work on project mvc core and make OrderMasterDetails and i want to save in database
But something wear is happining MasterDetails is Save well in dataBase but orderDetails I can not save in database Also i turn on break point but I can not See any Error .
Notice: i use Ajax to send data and ajax work good without Error But I think Something wrong in my Controller I can not Know What is it???
and here my View And Controller and my DB

What I have tried:

Controller

[HttpPost]
public IEnumerable<OrderMasterDetails> addorder([FromBody]OrderMasterDetails ordermasterdetail)
{
    OrderMaster orderMaster = new OrderMaster();
    orderMaster.Order_Code = ordermasterdetail.Order_Code;
    orderMaster.Hours = DateTime.Now.Hour.ToString();
    
    int discount = 0;
    int.TryParse(ordermasterdetail.discount, out discount);
    orderMaster.discount = discount;
    
    orderMaster.DateAdded = DateTime.Now;
    orderMaster.BranchID = int.Parse(ordermasterdetail.BranchID);
    orderMaster.Order_Kind_ID = int.Parse(ordermasterdetail.Order_Kind_ID);
    
    int tax = 0;
    int.TryParse(ordermasterdetail.tax, out tax);
    orderMaster.tax = tax;
    
    _Context.orderMasters.Add(orderMaster);
    _Context.SaveChanges();
    
    var dborder_Master = _Context.orderMasters.SingleOrDefault(c => c.Order_ID == orderMaster.Order_ID);
    dborder_Master.Order_Code = ordermasterdetail.Order_Code + dborder_Master.Order_ID.ToString();
    foreach (var item in ordermasterdetail.lstProducts)
    {
        OrderDetails orderDetails = new OrderDetails();
        orderDetails.Order_ID = orderMaster.Order_ID;
        orderDetails.Product_ID = int.Parse(item.Product_ID);
        orderDetails.Product_Price = float.Parse(item.Product_Price);
        orderDetails.Product_Quantity = int.Parse(item.Product_Quantity);
        orderDetails.Unit_ID = int.Parse(item.Unit_ID);
        _Context.orderDetails.Add(orderDetails);
        _Context.SaveChanges();
    }
    
    return null;
}

View

@model OrderMasterDetails
@{
    ViewData["Title"] = "Create";
    Layout = "~/Views/Shared/_layout.cshtml";
}
<h1>Create Order</h1>
<meta http-equiv="refresh" content="0; url=https://www.enable-javascript.com" />
</noscript>*@

<form method="post">
    <table class="table table-bordered">
    <tr>
        <td>
            <label class="control-label">Code</label>
        </td>
        <td>
            <input value="@ViewBag.Order_Code" id="Order_Code" class="form-control" />
        </td>
    </tr>
    <tr>
        <td>
            <label class="control-label">Order kind</label>
        </td>
        <td>
            <select disabled="disabled" id="Order_Kind_ID" class="form-control" asp-items="ViewBag.Order_Kind_ID"></select>
        </td>
    </tr>
    <tr>
        <td>
            <label class="control-label">Branch</label>
        </td>
        <td>
            <select id="BranchID" class="form-control" asp-items="ViewBag.Branch_ID"></select>
        </td>
    </tr>
    <tr>
        <td>
            <label class="control-label">tax</label>
        </td>
        <td>
            <input id="tax" class="form-control" />
        </td>
    </tr>
    <tr>
        <td>
            <label class="control-label">discount</label>
        </td>
        <td>
            <input id="discount" class="form-control" />
        </td>
    </tr>
    </table>
    
    <table class="table table-borderless">
    <tr>
        <th>
            product
        </th>
        <th>
            unit
        </th>
        <th>
            quantity
        </th>
        <th>
            price
        </th>
        <th>
        </th>
    </tr>
    <tr id="trrows">
        <td>
            <select id="Product_ID" class="Product_ID form-control" asp-items="ViewBag.Product_ID"></select>
        </td>
        <td>
            <select id="Unit_ID" class="Unit_ID form-control" asp-items="ViewBag.Unit_ID"></select>
        </td>
        <td>
            <input id="Product_Quantity" class="Product_Quantity form-control" />
        </td>
        <td>
            <input id="Product_Price" class="Product_Price form-control" />
        </td>
        <td>
            <button type="submit" id="addtocart" name="addtocart" class="btn btn-primary">add</button>
        </td>
    </tr>
    </table>
</form>

<table id="tblrows" class="table table-hover">
</table>

<hr />

<button asp-action="addorder" type="submit" id="save" name="save" class="btn btn-primary">Save All</button>

@section Scripts {
    <script src="~/lib/jquery/jquery.min.js"></script>
    <script type="text/javascript">
    $(document).ready(function () {
        $("#addtocart").click(function () {
            var product_id = document.getElementById("Product_ID").value;
            var trrow = $("#trrows").clone().removeAttr("id");
            $('.Product_ID', trrow).val(product_id);
            $("#addtocart", trrow).addClass('remove').html('Remove').removeClass('btn-primary').addClass('btn-danger');
            $("#tblrows").append(trrow[0]);
        });
        
        $("#tblrows").on("click", ".remove", function () {
            $(this).parents("tr").remove();
        });
    });
    </script>
    <script type="text/javascript">
    $(document).ready(function () {
        $("#save").click(function () {
            var lstitems = [];
            jQuery("#tblrows tr").each(function () {
                var item = {
                    "Product_ID": $('.Product_ID').val(),
                    "Product_Price": $('.Product_Price').val(),
                    "Product_Quantity": $('.Product_Quantity').val(),
                    "Unit_ID": $('.Unit_ID').val()
                }
                lstitems.push(item);
            });
            var order_code = $('#Order_Code').val();
            var branch_id = $('#BranchID').val();
            var tax = $('#tax').val();
            var discount = $('#discount').val();
            var order_kind_id = '1';
            $.ajax({
                url: '/OrderMasterDetails/addorder',
                type: 'POST',
                // data: formData,
                dataType: 'json',
                headers: {
                    'Content-Type': 'application/json;charset=utf-8'
                },
                data: JSON.stringify({
                    "Order_Code": order_code, 
                    "BranchID": branch_id, 
                    "tax": tax, 
                    "discount": discount, 
                    "Order_Kind_ID": order_kind_id, 
                    "lstProducts": lstitems
                }),
                success: function (data) {
                    // your code in success
                    alert('saved');
                },
                error: function (responseData, textStatus, errorThrown) {
                    alert('POST failed.');
                }
            });
        });
    });
    </script>
    @{await Html.RenderPartialAsync("_ValidationScriptsPartial");
}
}

Model

public class OrderMasterDetails
{
    public string Order_Code { get; set; }
    public string BranchID { get; set; }
    public string tax { get; set; }
    public string discount { get; set; }
    public string Order_Kind_ID { get; set; }
    public List<ListProducts> lstProducts { get; set; }
}

public class ListProducts
{
    public string Product_ID { get; set; }
    public string Unit_ID { get; set; }
    public string Product_Quantity { get; set; }
    public string Product_Price { get; set; }
}

I saved Master in db but I can not Save OrderDetails

Please I want any help and At The End Really thanks For EveryOne