C#comebox实现三级联动

最新推荐文章于 2023-01-09 16:15:34 发布

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最新推荐文章于 2023-01-09 16:15:34 发布 · 1k 阅读

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本文介绍了如何使用C#的ComboBox控件实现三级联动效果。通过创建 Province, City 和 Coun 三个表，并关联PID, PId 和 CId 字段，实现从省到市再到县的联动选择功能。" 84029022,8203405,MySQL到PostgreSQL的数据迁移指南,"['数据库迁移', 'MySQL', 'PostgreSQL', 'Drupal', '数据转换']

1.运用ComboBox的控件建立效果，如右图：

2.建立三个表，第一个Province表: PID,PName;第二个为city表: CId,CName,PId;第三个为coun表:CounID,CounName,CId;

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Data.SqlClient;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace 三级联动
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();

    }
    private void BindProvince()
    {
        SqlConnection conn = new SqlConnection("Data Source=.;Initial Catalog=三级联动;Integrated Security=True");
        SqlDataAdapter da = new SqlDataAdapter("select PID, PName from prov", conn);
        DataTable dt = new DataTable();
        da.Fill(dt);

        //for (int i = 0; i < dt.Rows.Count; i++)
        //{
        //    this.comboBox1.Items.Add(dt.Rows[i]["PName"].ToString());
        //}

        this.comboBox1.DataSource = dt;
        this.comboBox1.DisplayMember = "PName";
       

    }
    private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
    {
        if (comboBox1.SelectedIndex > -1)
        {
            DataRowView drv = (DataRowView)comboBox1.SelectedItem;
            string pId = drv.Row["PID"].ToString();
            SqlConnection conn = new SqlConnection("Data Source=.;Initial Catalog=三级联动;Integrated Security=True");
            SqlDataAdapter da = new SqlDataAdapter("select CId, CName from City where PId='" + pId + "'", conn);
            DataSet ds = new DataSet();
            da.Fill(ds,"City");
            DataTable dtUser = ds.Tables["City"];
            comboBox2.DataSource = dtUser;
            comboBox2.DisplayMember = "CName";
            comboBox2.ValueMember = "CID";
         
        }
    }

    private void Form1_Load_1(object sender, EventArgs e)
    {
        BindProvince()