dropdownlist for city , satate

Refer Following Links....

http://www.aspsnippets.com/Articles/Creating-Cascading-DropDownLists-in-ASP.Net.aspx[^]

You should bind your data when the selected index change event.

protected void dlstcountry_SelectedIndexChanged(object sender, EventArgs e)
    {
        string messg = "";
        DataTable dtstate = new DataTable();

       
      sql = "Select State from Tablename where Country='"+dlstcountry.SelectedValue.Trim()+ "'";
        dtstate = GetRecord(sql, ref messg);
        dlststate .Items.Clear();
        if (dtstate .Rows.Count != 0)
        {
            for (int i = 0; i < dtstate .Rows.Count; i++)
            {
                dlststate.Items.Add(new ListItem(dtstate .Rows[i][0].ToString()));
            }
        }

    }

Hope Be helpful,
Theingi Win

This will help you
Simple Way to Implement Country/State/City Dropdown List in ASP.NET (VB)[^]

check below link
http://www.asp.net/ajaxLibrary/AjaxControlToolkitSampleSite/CascadingDropDown/CascadingDropDown.aspx[^]

Hi, Pal

When ur working with drop down list control u need to understand what is server side code and what is client side code

when u working with dropdown list u simply add AutoPostBack = "True" to the control in the page. that's it when ur change the selected item in list it fires the

ddlCtrl_OnSelectedIndexChanged(object sender, EventArgs e) 

event and corosponding code is executed.

For ur problem

Simple Solution is Put the 3 dropdown controls in a updatepanel and write a code like

ddc1_OnSelectedIndexChanged(object sender, EventArgs e)
{
ddc2.datasource = ds1 //Dataset Or List
}

<pr2 lang="cs">ddc2_OnSelectedIndexChanged(object sender, EventArgs e)
{
ddc3.datasource = ds2 //Dataset Or List
}</pr2>

Thanks...

Hi,

Here is my solution check this once

<asp:scriptmanager id="ScriptManager1" runat="server" xmlns:asp="#unknown">
   </asp:scriptmanager>
   <asp:updatepanel id="UpdatePanel1" runat="server" xmlns:asp="#unknown">
      <contenttemplate>
        <table width="100&" align="center">
         <tr>
           <td>Select Contry</td>
           <td>
               <asp:dropdownlist id="DropDownList1" runat="server" datatextfield="cname" datavaluefield="cid">
                   onselectedindexchanged="DropDownList1_SelectedIndexChanged">
               </asp:dropdownlist>
           </td>
         </tr>
         <tr>
           <td>Select State</td>
           <td><asp:dropdownlist id="DropDownList2" runat="server" datatextfield="sname" datavaluefield="sid">
                   onselectedindexchanged="DropDownList2_SelectedIndexChanged">
               </asp:dropdownlist></td>
         </tr>
         <tr>
           <td>Select City</td>
           <td><asp:dropdownlist id="DropDownList3" runat="server" datatextfield="cityname" datavaluefield="cityid">
               </asp:dropdownlist></td>
         </tr>
        </table>
      </contenttemplate>
   </asp:updatepanel>

In the code behind file contains following code

AddressBLL objbll = new AddressBLL();
//this is your BLL class object for accessing all methods
protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        fillcontry();
    }

}
public void fillcontry()
{
    DataTable dt = new DataTable();
    dt = objbll.getAllContries();
    DropDownList1.DataSource = dt;
    DropDownList1.DataBind();
}


protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{
     DataTable dt = new DataTable();
    dt = objbll.getStatesbyCid(DropDownList1.SelectedIndex);
    DropDownList2.DataSource = dt;
    DropDownList2.DataBind();
}
protected void DropDownList2_SelectedIndexChanged(object sender, EventArgs e)
{
    DataTable dt = new DataTable();
    dt = objbll.getCitiesbySid(DropDownList2.SelectedIndex );
    DropDownList3.DataSource = dt;
    DropDownList3.DataBind();
}

All the Best