Regarding to the C# code

Question

When I select one item from one dropdown list,I want to get particular items which are belongs to that item in another dropdown list below to that. Likewise I have 4 dropdown lists and they are depends on one to next and next to another dropdown and etc.
I want Quick Replay plz..

Venkat Kumar · Answer

hai you need to create 4 tables for 4 dropdowns. lets suppose: table1:tblcountry id ->primary key countryname-> varchar(100) table2:tblstate id ->primary key statename-> varchar(100) countryid->forigen key of tblcountry(id) you need to relate the tables like above. Step1:During page_Load bind all the countries to dropdown1 and don't bind remaining dropdown values. step2: on dropdown1 selected index changed based on id of tblcountry fetch the data from database and display in dropdown2. We have primary key and foreign key relation for those tblcountry and tblstate tables. s o we can fetch the data by using id of tblcountry.

Thavaselvan P · Answer

html xmlns =http://www.w3.org/1999/xhtml> head runat =server> title > CasCading Dropdowns Sample title > head > body > form id =form1 runat =server> div > table align =center> tr > td > Select Country: td > td > asp : DropDownList ID =ddlCountry runat =server AutoPostBack =true onselectedindexchanged =ddlCountry_SelectedIndexChanged> asp : DropDownList > td > tr > tr > td > Select State: td > td > asp : DropDownList ID =ddlState runat =server AutoPostBack =true onselectedindexchanged =ddlState_SelectedIndexChanged> asp : DropDownList > td > tr > tr > td > Select Region: td > td > asp : DropDownList ID =ddlRegion runat =server> asp : DropDownList > td > tr > table > div > form > body > html > In code behind write like this private String strConnection = Data Source=XZCBJ017550;Initial Catalog=MySamplesDB;Integrated Security=True ; protected void Page_Load( object sender EventArgs e) { if (!IsPostBack) { BindContrydropdown(); } } /// /// Bind COuntrydropdown /// protected void BindContrydropdown() { //conenction path for database SqlConnection con = new SqlConnection (strConnection); con.Open(); SqlCommand cmd = new SqlCommand ( select * from CountryTable  con); SqlDataAdapter da = new SqlDataAdapter (cmd); DataSet ds = new DataSet (); da.Fill(ds); con.Close(); ddlCountry.DataSource = ds; ddlCountry.DataTextField = CountryName ; ddlCountry.DataValueField = CountryID ; ddlCountry.DataBind(); ddlCountry.Items.Insert(0 new ListItem ( --Select--  0 )); ddlState.Items.Insert(0 new ListItem ( --Select--  0 )); ddlRegion.Items.Insert(0 new ListItem ( --Select--  0 )); } /// /// Bind State Dropdown Based on CountryID /// /// /// protected void ddlCountry_SelectedIndexChanged( object sender EventArgs e) { int CountryID = Convert .ToInt32(ddlCountry.SelectedValue); SqlConnection con = new SqlConnection (strConnection); con.Open(); SqlCommand cmd = new SqlCommand ( select * from StateTable where CountryID= +CountryID con); SqlDataAdapter da = new SqlDataAdapter (cmd); DataSet ds = new DataSet (); da.Fill(ds); con.Close(); ddlState.DataSource = ds; ddlState.DataTextField = StateName ; ddlState.DataValueField = StateID ; ddlState.DataBind(); ddlState.Items.Insert(0 new ListItem ( --Select--  0 )); if (ddlState.SelectedValue== 0 ) { ddlRegion.Items.Clear(); ddlRegion.Items.Insert(0 new ListItem ( --Select--  0 )); } } /// /// Bind Region dropdown based on Re /// /// /// protected void ddlState_SelectedIndexChanged( object sender EventArgs e) { int StateID = Convert .ToInt32(ddlState.SelectedValue); SqlConnection con = new SqlConnection (strConnection); con.Open(); SqlCommand cmd = new SqlCommand ( select * from RegionTable where StateID= + StateID con); SqlDataAdapter da = new SqlDataAdapter (cmd); DataSet ds = new DataSet (); da.Fill(ds); con.Close(); ddlRegion.DataSource = ds; ddlRegion.DataTextField = RegionName ; ddlRegion.DataValueField = RegionID ; ddlRegion.DataBind(); ddlRegion.Items.Insert(0 new ListItem ( --Select--  0 )); }