in razor pages i am trying to save invoice data to sql table sales but But when you press the Save Invoice button, nothing happens, not even an error message, and the data is not saved I checked everything and found no errors
this is my cshtml.cs code
Note that there is a select list for both item names and customer names

using AfterFix.Pages.Clients;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.RazorPages;
using Microsoft.AspNetCore.Mvc.Rendering;
using System;
using System.Collections.Generic;
using System.Data.SqlClient;

namespace AfterFix.Pages.Sales
{
    public class NewSalesModel : PageModel
    {
        private readonly string _connectionString = "Data Source=DESKTOP-9CABSPL\SQLEXPRESS;Initial Catalog=mystore;Integrated Security=True;MultipleActiveResultSets=true";

        public class Invoice
        {
            // Define properties relevant to an invoice
            public string InvoiceNumber { get; set; }
            public DateTime InvoiceDate { get; set; } = DateTime.Now;
            public string CustomerName { get; set; }
            // Other properties as needed
        }
        // Fetch customers

        public List<SelectListItem> CustomerList { get; set; } = new List<SelectListItem>();
        public List<SelectListItem> Items { get; set; } = new List<SelectListItem>();
        public Invoice invoice = new Invoice();
        public string errorMessage = "";
        public string SuccsesMessage = "";

        public void OnGet()
        {
            using (var connection = new SqlConnection(_connectionString))
            {
                connection.Open();
                var query = "SELECT Id, Name FROM customers";
                using (var command = new SqlCommand(query, connection))
                {
                    var reader = command.ExecuteReader();
                    while (reader.Read())
                    {
                        var customerId = reader["Id"].ToString();
                        var customerName = reader["Name"].ToString();
                        CustomerList.Add(new SelectListItem
                        {
                            Value = customerId,
                            Text = customerName
                        });
                    }
                }
                // Fetch items
                var itemQuery = "SELECT Id, ItemName FROM items"; // Adjust the query according to your database schema
                using (var itemCommand = new SqlCommand(itemQuery, connection))
                {
                    var itemReader = itemCommand.ExecuteReader();
                    while (itemReader.Read())
                    {
                        var itemId = itemReader["Id"].ToString();
                        var itemName = itemReader["ItemName"].ToString();
                        Items.Add(new SelectListItem
                        {
                            Value = itemId,
                            Text = itemName
                        });
                    }
                }
            }
        }

        public int SelectedCustomerId { get; set; }
        //public int InvoiceId { get; set; } // For existing invoices (optional)
        // public string InvoiceNumber { get; set; }
        // public DateTime InvoiceDate { get; set; } = DateTime.Now;  // Defaults to current date
        // public int CustomerId { get; set; }
        // public string CustomerName { get; set; }

        public void OnPost()
        {
            invoice.InvoiceNumber = Request.Form["InvoiceNumber"];

            // Parse InvoiceDate
            if (!DateTime.TryParse(Request.Form["InvoiceDate"], out DateTime invoiceDate))
            {
                errorMessage = "";
                return;
            }
            invoice.InvoiceDate = invoiceDate;

            // Parse CustomerId
            // Parse the CustomerName from the appropriate form field
            string customerName = Request.Form["CustomerName"];

            // Validate if the parsed value is not null or empty
            if (string.IsNullOrEmpty(customerName))
            {
                errorMessage = "";
                return;
            }

            // Assign the parsed CustomerName to invoice.CustomerName
            invoice.CustomerName = customerName;


            // Validation
            if (string.IsNullOrEmpty(invoice.InvoiceNumber) ||
                invoice.InvoiceDate == DateTime.MinValue ||
                invoice.CustomerName == null)
            {
                errorMessage = "";
                return;
            }

            // Save to database
            try
            {
                string connectionString = "Server=DESKTOP-9CABSPL\SQLEXPRESS;Database=mystore;Trusted_Connection=True;MultipleActiveResultSets=true";
                using (SqlConnection connection = new SqlConnection(connectionString))

                {
                    string sql = "INSERT INTO sales (InvoiceNumber, InvoiceDate, CustomerName) VALUES (@InvoiceNumber, @InvoiceDate, @CustomerName);";
                    using (SqlCommand command = new SqlCommand(sql, connection))
                    {
                        command.Parameters.AddWithValue("@InvoiceNumber", invoice.InvoiceNumber);
                        command.Parameters.AddWithValue("@InvoiceDate", invoice.InvoiceDate);
                        command.Parameters.AddWithValue("@CustomerName", invoice.CustomerName);
                        command.ExecuteNonQuery();
                    }
                }

            }
            catch (Exception ex)
            {
                // Handle other unexpected exceptions
                // Handle the exception
                errorMessage = "";
                // Log the exception or handle it in another appropriate way
                // Log the exception details
            }

            // Clear input fields and set success message
            invoice.InvoiceNumber = "";
                invoice.InvoiceDate = DateTime.Now;
                invoice.CustomerName = "";
                SuccsesMessage = "";
                Response.Redirect("/sales/Index");
            }
            
        }
    }

and this cshtml code

@page
@model AfterFix.Pages.Sales.NewSalesModel
@{
    ViewData["Title"] = "New Sales Invoice";
}

<h1>New Sales Invoice</h1>

<form method="post" id="invoiceForm">
    <div class="form-group">
        <label for="invoiceNumber">Invoice Number:</label>
        <input type="text" id="invoiceNumber" name="InvoiceNumber" class="form-control" value="@Model.invoice.InvoiceNumber" />
    </div>
    <div class="form-group">
        <label for="invoiceDate">Invoice Date:</label>
        <input type="date" id="invoiceDate" name="InvoiceDate" class="form-control" value="@Model.invoice.InvoiceDate.ToString("yyyy-MM-dd")" />
    </div>
    <div class="form-group">
        <label for="customerName">Customer:</label>
        <select id="customerName" name="SelectedCustomerName" class="form-control " value="@Model.invoice.CustomerName" />
            <option value="">Select Customer</option>
            @foreach (var customer in Model.CustomerList)
            {
                <option value="@customer.Value">@customer.Text</option>
            }
        </select>
    </div>
    <table class="table" id="itemsTable">
        <thead>
            <tr>
                <th>Item</th>
                <th>Quantity</th>
                <th>Price</th>
                <th>Total Price</th>
                <th></th>
            </tr>
        </thead>
        <tbody>
            <tr>
                <td>
                    <select name="Items" class="form-control item" onchange="calculateTotal()">
                        <option value="">Select Item</option>
                        @foreach (var item in Model.Items)
                        {
                            <option value="@item.Value">@item.Text</option>
                        }
                    </select>
                </td>
                <td><input type="number" name="Quantities" class="form-control quantity" onchange="calculateTotal()" /></td>
                <td><input type="number" name="Prices" class="form-control price" onchange="calculateTotal()" /></td>
                <td><input type="number" name="TotalPrice" class="form-control total" readonly /></td>
                <td><button type="button" class="btn btn-danger" onclick="deleteRow(this)">Delete</button></td>
            </tr>
        </tbody>
    </table>
    <button type="button" class="btn btn-success" onclick="addRow()">Add Item</button>
    <br />
    <div class="form-group">
        <label for="totalPrice">Total Price:</label>
        <input type="number" id="totalPrice" name="TotalPrice" class="form-control" readonly />
    </div>
    <button type="submit" class="btn btn-primary">Save Invoice</button>
</form>

@section scripts {
    <script>
        function calculateTotal() {
            var rows = document.querySelectorAll("#itemsTable tbody tr");
            var total = 0;
            rows.forEach(function (row) {
                var quantity = parseFloat(row.querySelector(".quantity").value) || 0;
                var price = parseFloat(row.querySelector(".price").value) || 0;
                var totalPrice = quantity * price;
                row.querySelector(".total").value = totalPrice.toFixed(2);
                total += totalPrice;
            });
            document.getElementById("totalPrice").value = total.toFixed(2);
        }

        function deleteRow(btn) {
            var row = btn.closest("tr");
            row.parentNode.removeChild(row);
            calculateTotal();
        }

        function addRow() {
            var table = document.getElementById("itemsTable").getElementsByTagName('tbody')[0];
            var newRow = table.insertRow(table.rows.length);
            newRow.innerHTML = `
                                <td><select name="Items" class="form-control item" onchange="calculateTotal()"><option value="">Select Item</option>@foreach (var item in Model.Items)
        {
                        <option value="@item.Value">@item.Text</option>
        }</select></td>
                                <td><input type="number" name="Quantities" class="form-control quantity" onchange="calculateTotal()" /></td>
                                <td><input type="number" name="Prices" class="form-control price" onchange="calculateTotal()" /></td>
                                <td><input type="number" name="TotalPrice" class="form-control total" readonly /></td>
                                <td><button type="button" class="btn btn-danger" onclick="deleteRow(this)">Delete</button></td>
                            `;
        }


    </script>
}