Combobox items related records display in datagridview

In this blog we will know when we select any items from combobox related records will be displayed in datagridview.

In this blog we will know when we select any items from combobox related records will be displayed in datagridview.

App.config

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<appSettings>
<add key="dsn" value="Provider=Microsoft.Jet.OLEDB.4.0;Data Source=..\EMP.mdb" />
</appSettings>
</configuration>
 
Form1.cs

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.OleDb;
namespace Combobox_related_datagridview
{
    public partial class Form1 : Form
    {
        string ConnectionString = System.Configuration.ConfigurationSettings.AppSettings["dsn"];
        OleDbCommand com;
        OleDbDataAdapter oledbda;
        DataSet ds;
        string str;

        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            comboBox1.Text="Select any name";
            comboBox1.Items.Add("Select any name");
            OleDbConnection con = new OleDbConnection(ConnectionString);
            con.Open();
            str = "select * from student";
            com = new OleDbCommand(str, con);
            OleDbDataReader reader = com.ExecuteReader();
            while (reader.Read())
            {
                comboBox1.Items.Add(reader["sname"].ToString());
            }
            reader.Close();
            con.Close();
        }

        private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
        {
            OleDbConnection con = new OleDbConnection(ConnectionString);
            con.Open();
            str = "select * from student where sname='" + comboBox1.Text + "'";
            com = new OleDbCommand(str, con);
            oledbda = new OleDbDataAdapter(com);
            ds = new DataSet();
            oledbda.Fill(ds, "student");
            dataGridView1.DataMember = "student";
            dataGridView1.DataSource = ds;
            con.Close();
        }
    }
}