---

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 WindowsFormsApp14
{
    enum TimerState { Enabled, Disabled };
    public partial class Form1 : Form
    {
        TimerState state;
        TimeSpan remain;
        public Form1()
        {
            state = TimerState.Disabled;
            remain = TimeSpan.Zero;
            InitializeComponent();
        }

        private void btnStart_Click(object sender, EventArgs e)
        {
            if (state == TimerState.Disabled)
            {
                btnStart.Text = "Stop";
                numMin.Enabled = numSec.Enabled = false;
                state = TimerState.Enabled;
                remain = new TimeSpan (0, (int)numMin.Value, 
                    (int)numSec.Value);
                lblOut.Text = remain.ToString(@"mm\:ss");
            }
            else
            {
                btnStart.Text = "Pusk";
                numMin.Enabled = numSec.Enabled = true;
                numMin.Value = remain.Minutes;
                numSec.Value = remain.Seconds;
                state = TimerState.Disabled;
            }

        }
        private void timer_Tick(object sender, EventArgs e)
        {
            if (state == TimerState.Disabled)
            {

            }
            else
            {
                remain = remain.Subtract(new TimeSpan(0, 0, 1));
                lblOut.Text = remain.ToString(@"mm\:ss");
                if (remain == TimeSpan.Zero)
                {
                    
                    btnStart.Text = "Pusk";
                    numMin.Enabled = numSec.Enabled = true;
                    numMin.Value = numSec.Value = 0;
                    state = TimerState.Disabled;
                    MessageBox.Show("Время заданного интервала истекло!", "Таймер", MessageBoxButtons.OK, MessageBoxIcon.Information);

                }

            }
        }
        private void numTime_ValueChanged(object sender, EventArgs e)
        {
            if (state == TimerState.Disabled)
            {
                if ((int)(numMin.Value) != 0 || numSec.Value != 0)
                    btnStart.Enabled = true;
                else
                    btnStart.Enabled = false;
            }
            else
            {

            }
        }
    }
}