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 WindowsFormsApp1
{
    public partial class login : Form
    {
        public login()
        {
            InitializeComponent();
        }
        private void Login_Load(object sender, EventArgs e)
        {
            label1.Text = "+";
            label2.Text = "=";
            button1.Text = "计算";
        }

        private void Button1_Click_1(object sender, EventArgs e)
        {
            int a, b, c;

            /*try
            {
                a = Convert.ToInt32(textBox1.Text);
                b = Convert.ToInt32(textBox2.Text);
            }
            catch (Exception)
            {

                MessageBox.Show("请输入整数");
                return;//不执行下面的语句了  退出这个方法
            }
            a = Convert.ToInt32(textBox1.Text);
            b = Convert.ToInt32(textBox2.Text);*///上面的检查也是可以的
            if (int.TryParse(textBox1.Text, out a) == false)
            {
                MessageBox.Show("请输入整数");
                return;
            }
            if (!int.TryParse(textBox2.Text, out b))
            //格式： int.TryParse(x,out y) //x是要转化的字符串，y是一个int 型的变量；
            {
                MessageBox.Show("请输入整数");
                return;
            }
            c = a + b;
            textBox3.Text = Convert.ToString(c);
        }
    }
}