KOP/Components/Visual/UserControlIntegerInput.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 UserControlIntegerInput : UserControl
    {
        private event EventHandler? _elementChanged;
        private event Action? _errorOccured;
        public string Error { get; private set; }
        public int? InputtedInteger
        {
            get
            {
                if (checkBoxNullable.Checked)
                {
                    return null;
                }
                if (textBoxInteger.Text.Equals(string.Empty) || textBoxInteger.Text == null)
                {
                    throw new UncheckedNullException("Input was null, but checkbox wasnt checked");
                }
                if (Int32.TryParse(textBoxInteger.Text, out var number))
                {
                    return number;
                }
                throw new UnexpectedTypeException("Input was non integer");
            }
            set
            {
                textBoxInteger.Text = value.ToString();
                checkBoxNullable.Checked = value == null;
            }
        }
        public event EventHandler ElementChanged
        {
            add { _elementChanged += value; }
            remove { _elementChanged -= value; }
        }
        public event Action AnErrorOccurred
        {
            add { _errorOccured += value; }
            remove { _errorOccured -= value; }
        }
        public UserControlIntegerInput()
        {
            InitializeComponent();
            Error = string.Empty;
        }

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

        private void checkBoxNullable_CheckedChanged(object sender, EventArgs e)
        {
            textBoxInteger.Enabled = !checkBoxNullable.Checked;
            textBoxInteger.Text = null;
            _elementChanged?.Invoke(this, e);
        }
    }
}