第四次作业

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 WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        public static int count = 0;
        private int t = 60;
        public static int right = 0;
        public int result;
        private void button5_Click(object sender, EventArgs e)
        {
            try
            {
                t = int.Parse(textBox4.Text);
                if (t > 0)
                {
                    label2.Text = t.ToString();
                    textBox4.Enabled = false;
                }
                else
                {
                    MessageBox.Show("输入数不能小于1，不能也带小数！");
                    return;
                }
            }
            catch (Exception)
            {
                
                throw;
            }
            timer1.Enabled = true;
            timer1.Interval = 1000;
            timer1.Start();
            Random();

        }
        private void Random()
         {
            Random ab = new Random();

            int a, b;
            a = ab.Next(1, 11);
            b = ab.Next(1, 11);
            textBox1.Text = a.ToString();
            textBox2.Text = b.ToString();
            textBox3.Text = "";
            count++;   

        }
        private void timer1_Tick(object sender, EventArgs e)
        {
            if (t <= 0)
            {
                timer1.Enabled = false;
                textBox3.Enabled = false;
                MessageBox.Show("时间到！");
                textBox3.Enabled = false;
            }
            t = t - 1;
            label2.Text = t.ToString();
            

       }

        private void button1_Click(object sender, EventArgs e)
        {
            label3.Text = "+";
        }

        private void button2_Click(object sender, EventArgs e)
        {
            label3.Text = "-";
        }

        private void button3_Click(object sender, EventArgs e)
        {
            label3.Text ="*";
        }

        private void button4_Click(object sender, EventArgs e)
        {
            label3.Text = "/";
        }

        private void textBox3_KeyDown(object sender, KeyEventArgs e)
        {
            
            if (e.KeyCode == Keys.Enter)
            {
                switch (label3.Text)
                {
                    case "+":
                        result = int.Parse(textBox1.Text) + int.Parse(textBox2.Text);
                        break;
                    case "-":
                        result = int.Parse(textBox1.Text) - int.Parse(textBox2.Text);
                        break;
                    case "*":
                        result = int.Parse(textBox1.Text) * int.Parse(textBox2.Text);
                        break;
                    case "/":
                        result = int.Parse(textBox1.Text) / int.Parse(textBox2.Text);
                        break;
                         }

                if (textBox3.Text == result.ToString())
                {

                    right++;
                    Random();
                }
                else
                {
                    Random();
                }
                           
            }
        }


        private void button6_Click(object sender, EventArgs e)
        {
            textBox3.Enabled = false;
            Form2 frm2 = new Form2();
            frm2.ShowDialog();
        }
        private void textBox3_KeyPress(object sender, KeyPressEventArgs e)
        {
            //在网上找到的关于用户输入非数字的判断，但是并不完善 ， 如果设置messagebox则会在按下回车键时弹出。
            if (!char.IsDigit(e.KeyChar))
            {
                e.Handled = true;
                //MessageBox.Show("请输入数字");
                
            }
        }
    }
}

我俩从网上找了不少例子，跟着勇勇哥学到了不少东西，我看不懂的代码都问他，他也很乐意给我说，
今天您告诉我们复制粘贴不好，我们也懂得，我们看到别人的代码之后呢，会去理解其中的意思，知其所以然。
当作例子用。