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  • C# comboBox实现省市两级联动(winform)

    新建一个win form应用程序,拖两comboBox控件。数据库见前一篇文章。

    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 省市
    {
    publicpartialclass Form1 : Form
    {
    public Form1()
    {
    InitializeComponent();
    }
     private void Form1_Load(object sender, EventArgs e)
            {
                using (SqlConnection conn = new SqlConnection("server=.;database=DBPromary;user id=sa;password=123456"))
                {
                    conn.Open();

                    using (SqlCommand cmd = conn.CreateCommand())
                    {
                        cmd.CommandText = "select proName from promary";

                        using (SqlDataReader reader = cmd.ExecuteReader())
                        {

                            while (reader.Read())
                            {
                                string name = reader.GetString(reader.GetOrdinal("proName"));

                                cb1.Items.Add(name);
                            }
                        }
                    }
                }

            }



    privatevoid comboBox1_SelectedIndexChanged(object sender, EventArgs e)
    {
    cb2.Items.Clear();
    using (SqlConnection conn =new SqlConnection("server=.;database=DBPromary;user id=sa;password=123456"))
    {
    conn.Open();

    using (SqlCommand cmd = conn.CreateCommand())
    {
    cmd.CommandText
    ="select cityName from city,promary where city.proID=promary.proID and promary.proName=@pname";
    cmd.Parameters.Add(
    new SqlParameter("pname",cb1.SelectedItem));

    using (SqlDataReader reader = cmd.ExecuteReader())
    {

    while (reader.Read())
    {
    string name = reader.GetString(reader.GetOrdinal("cityName"));

    cb2.Items.Add(name);
    }
    }
    }
    }

    }


    }
    }
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  • 原文地址:https://www.cnblogs.com/agile2011/p/2059110.html
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