try-catch中的message提示

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 Form2 : Form    {        public Form2()        {            InitializeComponent();        }        private void button1_Click(object sender, EventArgs e)        {            if (textBox1.TextLength == 0 || textBox2.TextLength == 0)            {                MessageBox.Show("请输入数：");                return;            }            try            {                double x = double.Parse(textBox1.Text);                double y = double.Parse(textBox2.Text);                double xy = x + y;                textBox3.Text = xy.ToString();            }            catch(Exception ex)            {                MessageBox.Show(ex.Message);//自动显示错误的原因            }        }    }}

运行结果：