C#语言学习--基础部分(六) －－异常处理

1,try catch finally,checked,unchecked,throw.注：try后面可以不跟catch语句，但后面要跟finally语句。可以同时跟catch,finally或者两者当中的一个，但不能什么都不跟。

a.WPF Demo:

 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace TryCatchStatement
{
    /// <summary>
    /// MainWindow.xaml 的交互逻辑
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, RoutedEventArgs e)
        {
            try
            {
                int num1 = int.Parse(txtNum1.Text);　//num1,num2的作用域在try语句块内。
                int num2 = int.Parse(txtNum2.Text);
                txtResult.Text = (num1 + num2).ToString();
            }
            catch (FormatException fExp)
            {
                MessageBox.Show(fExp.Message);

            }
            catch (OverflowException oExp)
            {
                MessageBox.Show(oExp.Message);
            }
            //catch (Exception ex) //捕获Exception异常写在最后
            //{
            //    MessageBox.Show(ex.Message);

            //}
        }
    }
}

b.Console Demo:(checked)

 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace CheckedUncheckedDemo
{
    class Program
    {
        static void Main(string[] args)
        {
            int number = int.MaxValue;
            try
            {
                checked
                {
                    number++;
                    Console.WriteLine(number);
                }
            }
            catch (Exception Exp)
            {
                Console.WriteLine(Exp.Message);
            }
        }
    }
}

(throw Demo)

 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ThrowDemo
{
    class Program
    {
        static void Main(string[] args)
        {
            int month = int.Parse(Console.ReadLine());
            try
            {
                string name = monthName(month);
            }
            catch (ArgumentOutOfRangeException Aexp)
            {
                Console.WriteLine(Aexp.Message);
            }
            finally {
                Console.WriteLine("程序结束");  //只要finally出现在try语句中，无论是抛出异常，是否有return语句最后都会执行finally语句.
            }
            //if (name == "")
            //{
            //    Console.WriteLine("您输入的月份的数值不正确");
            //}
            //else
            //{
            //    Console.WriteLine(name);
            //}
        }
        static string monthName(int month)
        {
            switch (month)
            {
                case 1:
                    return "一月";
                case 2:
                    return "二月";
                default:
                    //return "";
                    throw new ArgumentOutOfRangeException("您输入的月份不正确");
            }
 
        }
    }
}