in three tier how to populate ddl based on another ddl selec

Question

in three tier architecture how to populate ddl based on another ddl selected value

Satyapriya Nayak · Answer

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 { public partial class Form1 : Form { string ConnectionString = System.Configuration.ConfigurationSettings.AppSettings[dsn]; OleDbCommand com; OleDbDataAdapter oda; DataSet ds; string str; public Form1() { InitializeComponent(); } private void Form1_Load(object sender EventArgs e) { comboBox1.Items.Add(Choose CourseID); OleDbConnection con = new OleDbConnection(ConnectionString); con.Open(); str = select * from Courses; com = new OleDbCommand(str con); OleDbDataReader reader = com.ExecuteReader(); while (reader.Read()) { comboBox1.Items.Add(reader[CourseID]); } } private void comboBox1_SelectedIndexChanged(object sender EventArgs e) { comboBox2.Items.Clear(); OleDbConnection con = new OleDbConnection(ConnectionString); con.Open(); str = select * from Students where CourseID=' + comboBox1.Text.Trim() + '; com = new OleDbCommand(str con); OleDbDataReader reader = com.ExecuteReader(); while (reader.Read()) { comboBox2.Items.Add(reader[FirstName].ToString()); } con.Close(); reader.Close(); } } }

venkata kumar · Answer

hi first ddl selected change event pass values and get values and bind to second ddl