ProjectLib/ProjectLibrary/Forms/FReader.cs

using System;
using System.Windows.Forms;
using ProjectLibrary.Entities;
using ProjectLibrary.Repositories;

namespace ProjectLibrary.Forms
{
    public partial class FReader : Form
    {
        private readonly IReaderRepository _readerRepository;
        private int? _readerId;

        public int ID
        {
            set
            {
                try
                {
                    var reader = _readerRepository.ReadReaderById(value);

                    if (reader == null)
                    {
                        throw new InvalidOperationException($"Reader with ID {value} not found.");
                    }

                    txtName.Text = reader.Name;
                    txtReaderTicket.Text = reader.ReaderTicket.ToString();
                    

                    _readerId = value;
                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.Message, "[ Error : wrong data ]", MessageBoxButtons.OK, MessageBoxIcon.Error);
                    return;
                }
            }
        }

        public FReader(IReaderRepository readerRepository)
        {
            InitializeComponent();
            _readerRepository = readerRepository ?? throw new ArgumentNullException(nameof(readerRepository));
        }

        private void SaveBtn_Click(object sender, EventArgs e)
        {
            try
            {
                if (string.IsNullOrWhiteSpace(txtName.Text) || string.IsNullOrWhiteSpace(txtReaderTicket.Text))
                {
                    throw new Exception("[ Error : blank spaces were left, not enough information ]");
                }

                var reader = CreateReader();

                if (_readerId.HasValue)
                {
                    _readerRepository.UpdateReader(reader);
                }
                else
                {
                    _readerRepository.CreateReader(reader);
                }

                Close();
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message, "[ Error : while saving ]", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
        }

        private void DiscardBtn_Click(object sender, EventArgs e)
        {
            Close();
        }

        private Reader CreateReader()
        {
            return Reader.CreateEntity(
                _readerId ?? 0,
                txtName.Text,
                int.Parse(txtReaderTicket.Text)
            );
        }
    }
}