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 CountryId,CountryName 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 StateId,StateName 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 CityId,CityName 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...

how to create cascading dropdownlist without using postback?

Karthikeyan K

Karthikeyan K