how to create cascading dropdownlist without using postback?

Question

I have taken three cascading drop down list.

one for country,one for state and the last one for city..

when I select any country from the first dropdown the and then the second will be enabled and will show only that states of a country which i have selected in drop down list.

That is working properly but because of the Auto postback property is true so each time i select country then the page is refreshed then after i select state again the page is refreshed and for city also the page is refreshed.so the page is refreshed thrice.

that i don't want to do.so what should i do to avoid the thrice page refresh??

can I use Ajax cascading drop down list??

How??

Satyapriya Nayak · Answer

Untitled Page ForeColor=Red Width=100px> AppendDataBoundItems=true runat=server Height=20px Width=156px onselectedindexchanged=ddlcountry_SelectedIndexChanged Font-Bold=True ForeColor=#FF9900> ForeColor=Red Width=100px> AppendDataBoundItems =true runat=server Height=20px Width=155px onselectedindexchanged=ddlstate_SelectedIndexChanged Font-Bold=True ForeColor=#993300> ForeColor=Red Width=100px> runat=server Height=20px Width=155px Font-Bold=True ForeColor=#CCCC00> using System; using System.Collections; 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; namespace Country_state_city { public partial class _Default : System.Web.UI.Page { string strConnString = ConfigurationManager.ConnectionStrings[ConnectionString].ConnectionString; string str; SqlCommand com; SqlDataAdapter sqlda; DataSet ds; protected void Page_Load(object sender EventArgs e) { if (!IsPostBack) { bindcountry(); } } protected void ddlcountry_SelectedIndexChanged(object sender EventArgs e) { bindstate(); } protected void ddlstate_SelectedIndexChanged(object sender EventArgs e) { bindcity(); } public void bindcountry() { SqlConnection con = new SqlConnection(strConnString); con.Open(); str = select CountryIdCountryName from Country; com = new SqlCommand(str con); sqlda = new SqlDataAdapter(com); ds = new DataSet(); sqlda.Fill(ds Country); ddlcountry.Items.Clear(); ddlcountry.Items.Add(--Select--); ddlcountry.DataValueField = CountryId; ddlcountry.DataTextField = CountryName; ddlcountry.DataSource = ds; ddlcountry.DataMember = Country; ddlcountry.DataBind(); con.Close(); } public void bindstate() { SqlConnection con = new SqlConnection(strConnString); con.Open(); str = select StateIdStateName from State where Country_Id=' + ddlcountry.SelectedValue + '; com = new SqlCommand(str con); sqlda = new SqlDataAdapter(com); ds = new DataSet(); sqlda.Fill(ds State); ddlstate.Items.Clear(); ddlstate.Items.Add(--Select--); ddlstate.DataValueField = StateId; ddlstate.DataTextField = StateName; ddlstate.DataSource = ds; ddlstate.DataMember = State; ddlstate.DataBind(); con.Close(); } public void bindcity() { SqlConnection con = new SqlConnection(strConnString); con.Open(); str = select CityIdCityName from City where State_Id =' + ddlstate.SelectedValue + '; com = new SqlCommand(str con); sqlda = new SqlDataAdapter(com); ds = new DataSet(); sqlda.Fill(ds City); ddlcity.Items.Clear(); ddlcity.Items.Add(--Select--); ddlcity.DataValueField = CityId; ddlcity.DataTextField = CityName; ddlcity.DataSource = ds; ddlcity.DataMember = City; ddlcity.DataBind(); con.Close(); } } }

harshit wadhera · Answer

an error i.e if I select the one the it show the respective data in 2 dropdown and a the same time if i select the 2 option from 1 dropdown then it show both the data that i select first time and 2 time.

darsh antani · Answer

thnx...It is working...