form1.cs

来自「c#开发宝典 光盘内容。本光盘主要为书中的源程序」· CS 代码 · 共 75 行

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace Example17_7
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            cboCountry.SelectedIndex = 0;
        }

        private void cboCountry_SelectedIndexChanged(object sender, EventArgs e)
        {
            switch (cboCountry.SelectedIndex)
            {
                case 0:
                    cboCity.Items.Clear();
                    cboCity.Items.Add("北京");
                    cboCity.Items.Add("上海");
                    cboCity.Items.Add("天津");
                    cboCity.SelectedIndex = 0;
                    break;
                case 1:
                    cboCity.Items.Clear();
                    cboCity.Items.Add("纽约");
                    cboCity.Items.Add("华盛顿");
                    cboCity.Items.Add("芝加哥");
                    cboCity.SelectedIndex = 0;
                    break;
                case 2:
                    cboCity.Items.Clear();
                    cboCity.Items.Add("伦敦");
                    cboCity.Items.Add("曼彻斯特");
                    cboCity.Items.Add("伯明翰");
                    cboCity.SelectedIndex = 0;
                    break;
                case 3:
                    cboCity.Items.Clear();
                    cboCity.Items.Add("巴黎");
                    cboCity.Items.Add("慕尼黑");
                    cboCity.Items.Add("法兰克福");
                    cboCity.SelectedIndex = 0;
                    break;
                case 4:
                    cboCity.Items.Clear();
                    cboCity.Items.Add("莫斯科");
                    cboCity.Items.Add("圣彼得堡");
                    cboCity.Items.Add("海参崴");
                    cboCity.SelectedIndex = 0;
                    break;
                default:
                    cboCity.Items.Clear();
                    break;
            }
        }

        private void btnOK_Click(object sender, EventArgs e)
        {
            string mySelect = cboCountry.SelectedItem.ToString() + "：" + cboCity.SelectedItem.ToString();
            MessageBox.Show(mySelect, "国家城市列表", MessageBoxButtons.OK, MessageBoxIcon.Information);
        }
    }
}