The parameters dictionary contains a null entry for parameter 'linenumber' of non-nullable type 'system.int32'

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C#

ASP.NET5

Hi Team

I have a controller to edit a value from the form, but i keep getting this error on my controller that my property is nullable to int. How do i fix this issue? I try to put int? property name to fix this

What I have tried:

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lt;pre>// POST: OrderHeader/Edit
        [HttpPost]
        public ActionResult Edit(OrderLine orderLine)
        {
            if (ModelState.IsValid)
            {
                // Update the order line in the database
                UpdateOrderLine(orderLine);

                return RedirectToAction("Index");
            }

            return View(orderLine);
        }

        private void UpdateOrderLine(OrderLine orderLine)
        {
            string connectionString = "Data Source=DESKTOP-C5QD55P\\SQLEXPRESS;Initial Catalog=SalesOrder;Integrated Security=True";

            using(SqlConnection connection = new SqlConnection(connectionString))
            {
                connection.Open();
                string query = "UPDATE OrderLine SET ProductCode = @ProductCode, ProductType = @ProductType, CostPrice = @CostPrice, SalesPrice = @SalesPrice, Quantity = @Quantity WHERE LineNumber = @LineNumber";
                SqlCommand command = new SqlCommand(query, connection);
                command.Parameters.AddWithValue("@LineNumber", orderLine.LineNumber);
                command.Parameters.AddWithValue("@ProductCode", orderLine.ProductCode);
                command.Parameters.AddWithValue("@ProductType", orderLine.ProductType);
                command.Parameters.AddWithValue("@CostPrice", orderLine.CostPrice);
                command.Parameters.AddWithValue("@SalesPrice", orderLine.SalesPrice);
                command.Parameters.AddWithValue("@Quantity", orderLine.Quantity);

                command.ExecuteNonQuery();
            }
        }

        // Helper method to retrieve an order line by line number
        private OrderLine GetOrderLineByLineNumber(int lineNumber)
        {
            string connectionString = "Data Source=DESKTOP-C5QD55P\\SQLEXPRESS;Initial Catalog=SalesOrder;Integrated Security=True";

            OrderLine orderLine = null;
            using(SqlConnection connection = new SqlConnection(connectionString))
            {
                connection.Open();
                string query = "SELECT * FROM OrderLine WHERE LineNumber = @LineNumber";
                SqlCommand command = new SqlCommand(query, connection);
                command.Parameters.AddWithValue("@LineNumber", lineNumber);

                SqlDataReader reader = command.ExecuteReader();
                if(reader.Read())
                {
                    orderLine = new OrderLine
                    {
                        LineNumber = (int)reader["LineNumber"],
                        ProductCode = reader["ProductCode"].ToString(),
                        ProductType = reader["ProductType"].ToString(),
                        CostPrice = (decimal)reader["CostPrice"],
                        SalesPrice = (decimal) reader["SalesPrice"],
                        Quantity = (int) reader["Quantity"]
                    };
                }
                reader.Close();
            }

            return orderLine; // Return the retrieved order line or null if not found
        }

// model

public class OrderLine
    {
        
        public int OrderId { get; set; }
        public int LineNumber { get; set; }
        public string ProductCode { get; set; }
        public string ProductType { get; set; }
        public decimal CostPrice { get; set; }
        public decimal SalesPrice { get; set; }
        public int Quantity { get; set; }
        public List<OrderLine> OrderLines { get; set; }
    }

// view for edit

@model OrderApplicationXML.Models.OrderLine

@using (Html.BeginForm("Edit", "OrderHeader", FormMethod.Post))
{
    @Html.HiddenFor(model => model.LineNumber)

    <div class="form-group">
        @Html.LabelFor(model => model.ProductCode)
        @Html.TextBoxFor(model => model.ProductCode, new { @class = "form-control" })
    </div>

    <div class="form-group">
        @Html.LabelFor(model => model.ProductType)
        @Html.TextBoxFor(model => model.ProductType, new { @class = "form-control" })
    </div>

    <div class="form-group">
        @Html.LabelFor(model => model.CostPrice)
        @Html.TextBoxFor(model => model.CostPrice, new { @class = "form-control" })
    </div>

    <div class="form-group">
        @Html.LabelFor(model => model.SalesPrice)
        @Html.TextBoxFor(model => model.SalesPrice, new { @class = "form-control" })
    </div>

    <div class="form-group">
        @Html.LabelFor(model => model.Quantity)
        @Html.TextBoxFor(model => model.Quantity, new { @class = "form-control" })
    </div>

    <button type="submit" class="btn btn-primary">Update</button>
}

// routing config

routes.MapRoute(
                       name: "OrderHeaderEdit",
                       url: "OrderHeader/Edit/{LineNumber}",
                       defaults: new { controller = "OrderHeader", action = "Edit" }
                   );