How to write event on dynamically generated dropdownlist to fill other dropdownlist

Hi Archana,

Try this...

Default.aspx code

<%@ 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

3 Replies

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

Mayur Gujrathi14y ago

Archana your problem is to generate event or what to write in event

Create evnt like this

Button button = new Button();
button.Text = i.ToString();
button.Click += new EventHandler(Button_Click);

and do what you want as suggested by datta or nayak as per your need
Satyapriya Nayak14y ago
Hi Archana,

Try this...

Default.aspx code

<%@ 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
Datta Kharad14y ago
Hi

onselectedindexchanged="DropDownList1_SelectedIndexChanged" Width="139px">
Note:- AutoPostBack=True

protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{
        con=new SqlConnection("Your Connection string");
        con.Open();
        string sSQL = "Select SubCat from tabname where id='" + DropDownList1.SelectedValue + "'";
        da = new SqlDataAdapter(sSQL, con);
        DataSet ds=new DataSet();
        da.Fill(ds, "Tabname");

foreach (DataRow dr in ds.Tables["Tabname"].Rows)
{
DropDownList2.Items.Add(dr[0].ToString());
}
}