Parts.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using static System.Windows.Forms.VisualStyles.VisualStyleElement.Button;
using static System.Windows.Forms.VisualStyles.VisualStyleElement;
using System.Reflection.Emit;
using System.Xml.Linq;
using System.Security.AccessControl;
using System.Runtime.Remoting.Contexts;
using InventoryApp.Models;

namespace InventoryApp
    {
    public partial class Parts : Form
        {
        private readonly MainForm _mainForm;
        private bool isEditMode;
		private Part editingPart = null;
		private int _newPartId;

		public Parts(MainForm mainForm, Part partToEdit = null, int nextPartId = 1)
            {
            InitializeComponent();
            _mainForm = mainForm;
            isEditMode = partToEdit != null;
            editingPart = partToEdit;
			_newPartId = nextPartId;

			// Radio Button handlers
			RadioButtonInHouse.CheckedChanged += RadioButtonInHouse_CheckedChanged;
            RadioButtonOutsourced.CheckedChanged += RadioButtonOutsourced_CheckedChanged;

            if (isEditMode)
                {
                LoadPartData(partToEdit);
                TextBoxID.ReadOnly = true;
                this.Text = "Modify Part";
                label1.Text = "Modify Part";
                }
            else
                {
				TextBoxID.Text = _newPartId.ToString();
				this.Text = "Add Part";
                label1.Text = "Add Part";
                }

            this.FormClosed += (sender, e) => _mainForm.ClearSearchBox(); // Add this line to handle form close
            }

        private void LoadPartData(Part part)
        {
        TextBoxID.Text = part.ID.ToString();
        TextBoxName.Text = part.Name;
        TextBoxInventory.Text = part.InStock.ToString();
        TextBoxPrice.Text = part.Price.ToString();
        TextBoxMin.Text = part.Min.ToString();
        TextBoxMax.Text = part.Max.ToString();

        if (part is Inhouse inhouse)
            {
            RadioButtonInHouse.Checked = true;
            TextBoxMachineID.Text = inhouse.MachineID.ToString();
            TextBoxCompanyName.Text = "";
            }
        else if (part is Outsourced outsourced)
            {
            RadioButtonOutsourced.Checked = true;
            TextBoxCompanyName.Text = outsourced.CompanyName;
            TextBoxMachineID.Text = "";
            }
        }

        // Radio Button 1's code - In House - Machine ID
        private void RadioButtonInHouse_CheckedChanged(object sender, EventArgs e)
            {
            if (RadioButtonInHouse.Checked)
                {
                TextBoxMachineID.Visible = true;
                TextBoxCompanyName.Visible = false;
                labelThatChangesWithClick.Text = "Machine ID*";
                }
            }
        // Radio Button 2's code - Outsourced - Company Name
        private void RadioButtonOutsourced_CheckedChanged(object sender, EventArgs e)
            {
            if (RadioButtonOutsourced.Checked)
                {
                TextBoxMachineID.Visible = false;
                TextBoxCompanyName.Visible = true;
                labelThatChangesWithClick.Text = "Company*";
                }
            }

		private void ButtonSave_Click(object sender, EventArgs e)
			{
			try
				{
				string nameText = TextBoxName.Text.Trim();
				string inventoryText = TextBoxInventory.Text.Trim();
				string priceText = TextBoxPrice.Text.Trim();
				string minimum = TextBoxMin.Text.Trim();
				string maximum = TextBoxMax.Text.Trim();
				string machineIDText = TextBoxMachineID.Text.Trim();
				string companyNameText = TextBoxCompanyName.Text.Trim();

				if (string.IsNullOrWhiteSpace(nameText) ||
					string.IsNullOrWhiteSpace(inventoryText) ||
					string.IsNullOrWhiteSpace(priceText) ||
					string.IsNullOrWhiteSpace(minimum) ||
					string.IsNullOrWhiteSpace(maximum) ||
					(RadioButtonInHouse.Checked && string.IsNullOrWhiteSpace(machineIDText)) ||
					(RadioButtonOutsourced.Checked && string.IsNullOrWhiteSpace(companyNameText)))
					{
					MessageBox.Show("All fields must be filled.");
					return;
					}
				if (nameText.Any(char.IsDigit))
					{
					MessageBox.Show("The \"Name\" field cannot contain numbers.");
					return;
					}
				if (nameText.Length > 20)
					{
					MessageBox.Show("The \"Name\" must be fewer than 20 characters.");
					return;
					}
				if (!int.TryParse(inventoryText, out int inventory) || inventory < 0)
					{
					MessageBox.Show("Please enter a valid, non-negative integer for \"Inventory\" field.");
					return;
					}

				if (!decimal.TryParse(priceText, out decimal price) || price < 0)
					{
					MessageBox.Show("Please enter a valid, non-negative decimal number without symbols for \"Price\" field.");
					return;
					}

				if (!int.TryParse(minimum, out int min) || min < 0)
					{
					MessageBox.Show("Please enter a valid, non-negative integer for \"Minimum\" field.");
					return;
					}

				if (!int.TryParse(maximum, out int max) || max < 0)
					{
					MessageBox.Show("Please enter a valid, non-negative integer for \"Maximum\" field.");
					return;
					}
				if (min > max)
					{
					MessageBox.Show("\"Minimum\" number entered cannot be greater than current value of \"Maximum\"");
					return;
					}
				if (inventory < min || inventory > max)
					{
					MessageBox.Show("\"Inventory\" value must be between \"Min\" and \"Max\" values.");
					return;
					}
				if (companyNameText.Length > 20)
					{
					MessageBox.Show("The \"Company Name\" must be fewer than 20 characters.");
					return;
					}

				int partID = int.Parse(TextBoxID.Text);
				Part newPart;

				if (RadioButtonInHouse.Checked)
					{
					if (!int.TryParse(machineIDText, out int machineID) || machineID < 1)
						{
						MessageBox.Show("Please enter a valid integer for \"Machine ID\" greater than 0.");
						return;
						}
					newPart = new Inhouse(partID, nameText, price, inventory, min, max, machineID);
					}
				else
					{
					newPart = new Outsourced(partID, nameText, price, inventory, min, max, companyNameText);
					}

				if (isEditMode)
					{
					_mainForm.UpdatePart(newPart); // Replace part by matching ID
					}
				else
					{
					_mainForm.AddPart(newPart); // Add new part
					}
				this.DialogResult = DialogResult.OK;
				this.Close(); // Done!
				}
			catch (Exception ex)
				{
				MessageBox.Show($"An unexpected error occurred: {ex.Message}");
				}
			}

		// Code that makes the cancel Button work
		private void ButtonCancel_Click(object sender, EventArgs e)
            {
            this.Close(); // Closes the AddPart form
            }

        }
    }