how to use dropdownlist with example

Hi Narasiman,

choose Country corresponding state list appears

<%@ 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">

<title>Untitled Pagetitle>

head>

<body>

<div>

<br />

<asp:Label ID="Label3" runat="server" Text="Country" Width="100px">asp:Label>

<asp:DropDownList ID="DropDownList_country" runat="server" AutoPostBack="True"

onselectedindexchanged="DropDownList_country_SelectedIndexChanged">

asp:DropDownList>

<br />

<asp:Label ID="Label2" runat="server" Text="State" Width="100px">asp:Label>

<asp:DropDownList ID="DropDownList_state" runat="server">

asp:DropDownList>

div>

form>

body>

html>

Default.aspx.cs code

using System;

using System.Configuration;

using System.Data;

using System.Linq;

using System.Web;

using System.Web.Security;

using System.Web.UI;

using System.Web.UI.HtmlControls;

using System.Web.UI.WebControls;

using System.Web.UI.WebControls.WebParts;

using System.Xml.Linq;

using System.Data.SqlClient;

public partial class _Default : System.Web.UI.Page

{

string strConnString = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;

string str;

SqlCommand com;

protected void Page_Load(object sender, EventArgs e)

{

SqlConnection con = new SqlConnection(strConnString);

if (!IsPostBack)

{

DropDownList_country.Items.Add("Choose country");

con.Open();

str = "select country from area group by country";

com = new SqlCommand(str, con);

SqlDataReader reader = com.ExecuteReader();

while (reader.Read())

{

DropDownList_country.Items.Add(reader["country"].ToString());

}

reader.Close();

con.Close();

}

DropDownList_state.Items.Clear();

}

protected void DropDownList_country_SelectedIndexChanged(object sender, EventArgs e)

{

SqlConnection con = new SqlConnection(strConnString);

con.Open();

str = "select * from area where country='" +DropDownList_country.SelectedItem.Text + "'";

com = new SqlCommand(str, con);

SqlDataReader reader = com.ExecuteReader();

while (reader.Read())

{

DropDownList_state.Items.Add(reader["state"].ToString());

}

reader.Close();

con.Close();

}

Thanks

its very esay and simple

create a table in sql or you can use xml small database or add item hand

i give you code

void Country()
    {
        List _obj_country = new List();

        XmlDocument doc = new XmlDocument();
        String value = "";
        doc.Load("http://where.yahooapis.com/v1/countries?appid=[Yahoo API key]");
        XmlNodeList NewsList = doc.GetElementsByTagName("places");
        foreach (XmlNode node in NewsList)
        {
            foreach (XmlNode sub_node in node)
            {
                XmlElement ConnectionElement = (XmlElement)sub_node;
                value = ConnectionElement.GetElementsByTagName("name")[0].InnerText;
                _obj_country.Add(value);
            }
        }
        dd_country.DataSource = _obj_country;

        dd_country.DataBind();


    }

You need to get yahoo APi key then use this code
use this code

thanks

3 Replies

Know the answer? Post it — somebody with the same question will find it here.

Sam Hobbs14y ago
Also see these.
Satyapriya Nayak14y ago
Hi Narasiman,

choose Country corresponding state list appears

<%@ 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>Untitled Pagetitle>

head>

<body>

    <form id="form1" runat="server">

    <div>

    <br />

     <asp:Label ID="Label3" runat="server" Text="Country" Width="100px">asp:Label>

      <asp:DropDownList ID="DropDownList_country" runat="server" AutoPostBack="True"

            onselectedindexchanged="DropDownList_country_SelectedIndexChanged">

    asp:DropDownList>

        <br />

    <asp:Label ID="Label2" runat="server" Text="State" Width="100px">asp:Label>

    <asp:DropDownList ID="DropDownList_state" runat="server">

    asp:DropDownList>

    div>

    form>

body>

html>

Default.aspx.cs code

using System;

using System.Configuration;

using System.Data;

using System.Linq;

using System.Web;

using System.Web.Security;

using System.Web.UI;

using System.Web.UI.HtmlControls;

using System.Web.UI.WebControls;

using System.Web.UI.WebControls.WebParts;

using System.Xml.Linq;

using System.Data.SqlClient;

public partial class _Default : System.Web.UI.Page

{

    string strConnString = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;

    string str;

    SqlCommand com;

    protected void Page_Load(object sender, EventArgs e)

    {



        SqlConnection con = new SqlConnection(strConnString);



        if (!IsPostBack)

        {

            DropDownList_country.Items.Add("Choose country");

            con.Open();

            str = "select country from area group by country";

            com = new SqlCommand(str, con);

            SqlDataReader reader = com.ExecuteReader();

            while (reader.Read())

            {

                DropDownList_country.Items.Add(reader["country"].ToString());

            }

            reader.Close();

            con.Close();

        }

        DropDownList_state.Items.Clear();



    }

    protected void DropDownList_country_SelectedIndexChanged(object sender, EventArgs e)

    {

        SqlConnection con = new SqlConnection(strConnString);

        con.Open();

        str = "select * from area where country='" +DropDownList_country.SelectedItem.Text + "'";

        com = new SqlCommand(str, con);

        SqlDataReader reader = com.ExecuteReader();

        while (reader.Read())

        {

            DropDownList_state.Items.Add(reader["state"].ToString());

        }

        reader.Close();

        con.Close();

    }

}

Thanks
Dharmesh Sharma14y ago
its very esay and simple

create a table in sql or you can use xml small database or add item hand

i give you code

void Country()
    {
        List _obj_country = new List();

        XmlDocument doc = new XmlDocument();
        String value = "";
        doc.Load("http://where.yahooapis.com/v1/countries?appid=[Yahoo API key]");
        XmlNodeList NewsList = doc.GetElementsByTagName("places");
        foreach (XmlNode node in NewsList)
        {
            foreach (XmlNode sub_node in node)
            {
                XmlElement ConnectionElement = (XmlElement)sub_node;
                value = ConnectionElement.GetElementsByTagName("name")[0].InnerText;
                _obj_country.Add(value);
            }
        }
        dd_country.DataSource = _obj_country;

        dd_country.DataBind();


    }

You need to get yahoo APi key then use this code
use this code

thanks