计算器

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace 四则运算
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        public static int Count = 0;
        private int t = 60;
        public static int right = 0;

        private void button5_Click(object sender, EventArgs e)
        {
            label5.Text = t.ToString();
            timer1.Enabled = true;
            timer1.Interval = 1000;
            timer1.Start();
            RandomNum();
        }
        private void RandomNum()
        {
            Random random = new Random();
            int n1, n2;
            n1 = random.Next(1, 11);
            n2 = random.Next(1, 11);
            textBox1.Text = n1.ToString();
            textBox2.Text = n2.ToString();
            textBox3.Text = "";
            Count++;

        }
        

        private void textBox3_KeyDown(object sender, KeyEventArgs e)
        {
            int sum;
            string x = label1.Text;

            switch (x)
            {
                case "+":
                    sum = int.Parse(textBox1.Text) + int.Parse(textBox2.Text);
                    break;
                case "-":
                    sum = int.Parse(textBox1.Text) - int.Parse(textBox2.Text);
                    break;
                case "*":
                    sum = int.Parse(textBox1.Text) * int.Parse(textBox2.Text);
                    break;
                default:
                    sum = int.Parse(textBox1.Text) / int.Parse(textBox2.Text);
                    break;
            }



            if (e.KeyCode == Keys.Space)
            {
                if (textBox3.Text == sum.ToString())
                    right++;

                RandomNum();
            }

        }

        private void button6_Click(object sender, EventArgs e)
        {
            textBox3.Enabled =true;
            Form2 frm2 = new Form2();
            frm2.ShowDialog();
            timer1.Stop();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            label1.Text = "+";
        }

        private void button2_Click(object sender, EventArgs e)
        {
            label1.Text = "-";
        }

        private void button3_Click(object sender, EventArgs e)
        {
            label1.Text = "*";

        }

        private void button4_Click(object sender, EventArgs e)
        {
            label1.Text = "/";
        }

        private void timer1_Tick_1(object sender, EventArgs e)
        {
            if (t <= 0)
            {
                timer1.Enabled = false;
                textBox3.Enabled = false;
                MessageBox.Show("时间到！");
                textBox3.Enabled = false;
                Form2 frm2 = new Form2();
                frm2.ShowDialog();

            }
            t = t - 1;
            label5.Text = t.ToString();
        }
    }
}