how to deal with SelectedIndexChange of dropdownlist in Usercontrol Added dynamicaly

Question

hello everyone,
I have three DropDown list of Country,State,City in a User Control. I have populated the country DropDownList on page load of .ascx page ie. on UserControl. Now i want to populate the state ddl on selectedindexchange event of Countryddl bt finding difficulty to add that event on parent page.
plz can anyone help me to sortout this problem.

Tushar Malhotra · Answer

the asp code for the country ddl. onselectedindexchanged="country_SelectedIndexChanged1" ontextchanged="country_TextChanged" Width="176px"> One of the property of ddl is "AutoPostBack", which is to be set true... this allows to load the next ddl on its selection. Now the SelectedIndexChanged event of the country ddl protected void country_SelectedIndexChanged1(object sender, EventArgs e) { int ch = (int)country.SelectedIndex; switch (ch) { case 0: state.Items.Clear(); state.Items.Add("Delhi"); state.Items.Add("Punjab"); state.Items.Add("U.P."); state.Items.Add("Maharashtra"); break; case 1: state.Items.Clear(); state.Items.Add("Islamabad"); state.Items.Add("Punjab"); state.Items.Add("Karachi"); state.Items.Add("Lahor"); break; default: Label1.Text = "Select a country first"; break; } } The switch-case will check the index of the country ddl n will load the states. If u r loading the ddls from a database, then u have to fire a query as, "select state from country where country '" + country.Text + "'"; and then u will get a data set taht u can bound to state ddl...

Anusha Srivastava · Answer

I have done this coding on the User Control. 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; public partial class userControll_AddressUC : System.Web.UI. UserControl { /// /// Method for Page_Load /// /// /// /// #region "Page_Load" protected void Page_Load( object sender, EventArgs e) { try { if (!IsPostBack) { CountoryMaster oCountoryMaster = new CountoryMaster (); CountryDB oCountryDB = new CountryDB (); DataTable dtBindListCountry = oCountryDB.GetCountryName(oCountoryMaster); if (dtBindListCountry.Rows.Count > 0) { ddlAddCountry.DataSource = dtBindListCountry; ddlAddCountry.DataTextField = dtBindListCountry.Columns[ "country_name" ].ToString(); ddlAddCountry.DataValueField = dtBindListCountry.Columns[ "country_id" ].ToString(); ddlAddCountry.DataBind(); } dtBindListCountry.Dispose(); } } catch ( Exception ex) { throw ex; } } #endregion /// /// Method for ddlAddState_SelectedIndexChanged /// /// /// /// #region "BindCity" protected void BindCity( object sender, EventArgs e) { try { CityMaster oCityMaster = new CityMaster (); CityDB oCityDB = new CityDB (); oCityMaster.StateId = ddlAddState.SelectedValue; oCityMaster.CountryId = Convert .ToInt32(ddlAddCountry.SelectedValue); DataTable dtCity = oCityDB.getSelectCityByStateId(oCityMaster); if (dtCity.Rows.Count > 0) { ddlAddCity.DataSource = dtCity; ddlAddCity.DataTextField = dtCity.Columns[ "city_name" ].ToString(); ddlAddCity.DataValueField = dtCity.Columns[ "city_id" ].ToString(); ddlAddCity.DataBind(); } ddlAddCity.Items.Insert(0, new ListItem ( "Please Select..." , "-1" , true )); dtCity.Dispose(); } catch ( Exception ex) { throw ex; } } #endregion /// /// Method for ddlAddCountry_SelectedIndexChanged /// /// /// /// #region "BindState" protected void BindState( object sender, EventArgs e) { try { State oState = new State (); StateDb oStateDb = new StateDb (); oState.CountryId = Convert .ToInt32(ddlAddCountry.SelectedValue); DataTable dtState = oStateDb.getStateByCountry(oState); if (dtState.Rows.Count > 0) { ddlAddState.DataSource = dtState; ddlAddState.DataTextField = dtState.Columns[ "state_name" ].ToString(); ddlAddState.DataValueField = dtState.Columns[ "state_id" ].ToString(); ddlAddState.DataBind(); } ddlAddState.Items.Insert(0, new ListItem ( "Please Select..." , "-1" , true )); dtState.Dispose(); } catch ( Exception ex) { throw ex; } } #endregion asp : UpdatePanel ID ="UpnlAddDetails" runat ="server" UpdateMode ="Conditional"> ContentTemplate > table border ="0" cellpadding ="1" cellspacing ="3" width ="100%"> tr > td align ="left" width ="35%"> Country td > td align ="left" width ="65%"> asp : DropDownList ID ="ddlAddCountry" runat ="server" AutoPostBack ="true" CssClass ="fields" OnSelectedIndexChanged ="BindState"> asp : DropDownList > td > tr > tr > td align ="left" width ="35%"> State td > td align ="left" width ="65%"> asp : DropDownList ID ="ddlAddState" runat ="server" CssClass ="fields" AutoPostBack ="true" OnSelectedIndexChanged ="BindCity"> asp : DropDownList > td > tr > tr > td align ="left" width ="35%"> td > td align ="left" valign ="middle" width ="65%"> Other : asp : TextBox ID ="txtOtherState" runat ="server" CssClass ="INPUT-BOX"> asp : TextBox > td > tr > tr > td align ="left" width ="35%"> City td > td align ="left" width ="65%"> asp : DropDownList ID ="ddlAddCity" runat ="server" CssClass ="fields"> asp : DropDownList > td > tr > tr > td align ="left" width ="35%"> td > td align ="left" width ="65%"> Other : asp : TextBox ID ="txtOtherCity" runat ="server" CssClass ="INPUT-BOX"> asp : TextBox > td > tr > table > ContentTemplate > Triggers > asp : AsyncPostBackTrigger ControlID ="ddlAddCountry" EventName ="SelectedIndexChanged" /> asp : AsyncPostBackTrigger ControlID ="ddlAddState" EventName ="SelectedIndexChanged" /> Triggers > asp : UpdatePanel > And the Followingn on the parent page asp : DropDownList ID ="ddlAddressType" runat ="server" AutoPostBack ="true" CssClass ="fields" OnSelectedIndexChanged ="ddlAddressType_SelectedIndexChanged"> asp : ListItem Text ="...Select..." Value ="" Selected ="True"> asp : ListItem > asp : ListItem Text ="Home" Value ="Home"> asp : ListItem > asp : ListItem Text ="Business" Value ="Business"> asp : ListItem > asp : DropDownList > if (ddlAddressType.SelectedValue == "Home" ) { Control AddressHome = LoadControl( "~/userControll/AddressUC.ascx" ); pnlUCPermanent.Visible = true ; pnlUCPermanent.Controls.Add(AddressHome); pnlUCBussisns.Visible = false ; } if (ddlAddressType.SelectedValue == "Home" ) { Control AddressBuss = LoadControl( "~/userControll/AddressUC.ascx" ); pnlUCBussisns.Visible = true ; pnlUCBussisns.Controls.Add(AddressBuss); pnlUCPermanent.Visible = true ; } But the selected index change for the country ddl is not fired.

Tushar Malhotra · Answer

use switch-case in the country drop down list's SelectedIndexChanged event n maps its SelectedIndex property. On Case 0 write the code to add the items in the state ddl int indx = (int)country.SelectedIndex; switch(indx) { case 0://let the countrty be India state.Items.Add("Maharashtra"); // and so on.... } similarly do for the city ddl

how to deal with SelectedIndexChange of dropdownlist in Usercontrol Added dynamicaly

Answers (3)