PIbd-31_Danilov_V_V_COP-30/Components/CustomTextBox.cs

using Components.Exceptions;
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;

namespace Components
{
	public partial class CustomTextBox : UserControl
	{
		public event EventHandler ValueChanged;

		public CustomTextBox()
		{
			InitializeComponent();

			checkBoxNull.CheckedChanged += CheckBoxNull_CheckedChanged;
			textBoxInteger.TextChanged += TextBoxInteger_TextChanged;
		}

		public int? Value
		{
			get
			{
				if (checkBoxNull.Checked)
				{
					return null;
				}
				else
				{
					if (int.TryParse(textBoxInteger.Text, out int result))
					{
						return result;
					}
					else
					{
						throw new NotIntegerException("Ожидается целое число.");
					}
				}
			}
			set
			{
				checkBoxNull.Checked = !value.HasValue;
				textBoxInteger.Text = value.HasValue ? value.ToString() : string.Empty;
			}
		}

		private void TextBoxInteger_TextChanged(object sender, EventArgs e)
		{
			ValueChanged?.Invoke(this, e);
		}

		private void CheckBoxNull_CheckedChanged(object sender, EventArgs e)
		{
			textBoxInteger.Enabled = !checkBoxNull.Checked;
			ValueChanged?.Invoke(this, e);
		}
	}
}