WinForm 練習1

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 計算器
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            string a = textBox1.Text;
            string b = textBox2.Text;
            int i1, i2;
            if (!int.TryParse(a, out i1))
            {
                MessageBox.Show("第一個數格式錯誤，請重新輸入");
                return;  //需要調出
            }
            if(int.TryParse(b,out i2)==false)
            {
                MessageBox.Show("第二個數格式錯誤，請重新輸入");
                return;
            }
            int i3 = i1 + i2;
            textBox3.Text = Convert.ToString(i3);//i3.ToString()
        }
    }
}