In these articles i explained about "How to populate one dropdownlist values based on selection in another dropdownlist in asp.net by using c#."
HTML Markup : Design Page
Adding two dropdownlist to get country and city name
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head runat="server"> <title></title> </head> <body> <form id="form1" runat="server"> <table> <tr> <td>Choose Country First : </td> <td> <asp:DropDownList ID="ddl_country" runat="server" Width="150px" AutoPostBack="True" onselectedindexchanged="ddl_country_SelectedIndexChanged"> </asp:DropDownList> </td> </tr> <tr> <td>Choose City : </td> <td> <asp:DropDownList ID="ddl_city" runat="server" Width="150px"> </asp:DropDownList><br /> </td> </tr> <tr> <td colspan="2"> <asp:Button ID="btn_display" runat="server" Text="Display" onclick="btn_display_Click" /> </td> </tr> <tr> <td colspan="2"> <asp:Label ID="lbl_display" runat="server"></asp:Label> </td> </tr> </table> </form> </body> </html>
C# Coding
C# Coding : Namespace
using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.Web.UI.WebControls; using System.IO; using System.Configuration; using System.Data.OleDb; using System.Data; using System.Data.SqlClient;
C# Coding : Page Load
public partial class _Default : System.Web.UI.Page { SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["ddl"].ConnectionString); SqlCommand cmd; SqlDataAdapter da; DataSet ds = new DataSet(); string query; protected void Page_Load(object sender, EventArgs e) { if (!IsPostBack) { GetCountry(); ddl_city.Items.Insert(0, " No City Available "); } } }
C# Coding : Get Country
GetCountry()
method is used to get all countries data from database and bind into Dropdownlist Controlprivate void GetCountry() { query = "Select * from Country"; da = new SqlDataAdapter(query, con); da.Fill(ds); if (ds.Tables[0].Rows.Count > 0) { ddl_country.DataSource = ds; ddl_country.DataTextField = "countryname"; ddl_country.DataValueField = "countryid"; ddl_country.DataBind(); ddl_country.Items.Insert(0, new ListItem(" Choose Country ", "0")); ddl_country.SelectedIndex = 0; } }
C# Coding : Dropdownlist SelectedIndexChanged Event
protected void ddl_country_SelectedIndexChanged(object sender, EventArgs e) { ds.Clear(); string get_countryname, countryname; countryname = ddl_country.SelectedItem.Text; get_countryname = ddl_country.SelectedValue.ToString(); if (get_countryname != "0") { query = "Select cityid, cityname from City where countryid='" + get_countryname.ToString() + "'"; da = new SqlDataAdapter(query, con); da.Fill(ds); if (ds.Tables[0].Rows.Count > 0) { ddl_city.DataSource = ds; ddl_city.DataTextField = "cityname"; ddl_city.DataValueField = "cityid"; ddl_city.DataBind(); ddl_city.Items.Insert(0, new ListItem("Choose " + countryname.ToString() + " City ", "0")); ddl_city.SelectedIndex = 0; } } else { ddl_city.Items.Insert(0, " No City Available "); ddl_city.DataBind(); } }
C# Coding : Button Click Event
protected void btn_display_Click(object sender, EventArgs e) { string display; display = " Your Country : " + ddl_country.SelectedItem.Text + "
Your City : " + ddl_city.SelectedItem.Text + ""; lbl_display.Text = display; } }
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