省市数据--类的方式读取

 

http://www.programfan.com/blog/article.asp?id=28128

代码如下:

 

 

 

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;
using System.Data.SqlClient;


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

        private void Form1_Load(object sender, EventArgs e)
        {

            using (SqlConnection conn = new SqlConnection(@"Data Source=.;Initial Catalog=Database1.mdf;Integrated Security=True;Pooling=False"))
            {
                conn.Open();
                using (SqlCommand cmd = conn.CreateCommand())
                {
                    cmd.CommandText = "Select * from promary";

                    using (SqlDataReader dataRead = cmd.ExecuteReader())
                    {
                        while (dataRead.Read())
                        {
                            promaryItem Item = new promaryItem(); //注意此处不能写在using 外面

                            Item.id = dataRead.GetInt32( dataRead.GetOrdinal("proID"));
                            Item.name = dataRead.GetString( dataRead.GetOrdinal("proName"));
                            cmb_promary.Items.Add(Item);
                        }
                    }
                }

            }


        }

        private void cmb_promary_SelectedIndexChanged(object sender, EventArgs e)
        {
            promaryItem Item =(promaryItem)cmb_promary.SelectedItem;
            int proId = Item.id;
            cmb_city.Items.Clear();//clear the previous data
            using (SqlConnection conn = new SqlConnection(@"Data Source=.;Initial Catalog=Database1.mdf;Integrated Security=True;Pooling=False"))
            {
                conn.Open();
                using (SqlCommand cmd = conn.CreateCommand())
                {
                    //string sqlStr = @"Select * from city where proId = " + proId;
                    //cmd.CommandText = sqlStr;
                    //equals the under statement
                    cmd.CommandText = "Select * from city where proId = @proId";
                    cmd.Parameters.Add(new SqlParameter("proId", proId));

                    using (SqlDataReader dataRead = cmd.ExecuteReader())
                    {
                        while (dataRead.Read())
                        {
                            string cityName = dataRead.GetString( dataRead.GetOrdinal( "cityName") ); //read DataBase data
                           
                            cmb_city.Items.Add(cityName);
                           
                        }
                    }
                }

            }


          
        }
    }

    class promaryItem
    {
        public string name{get;set;}
        public int id{ get;set;}
    }
}

 

 

http://www.programfan.com/blog/article.asp?id=28128