in this code i will show u how to cascade two dropdownlist, for gxample if u have two dropdownlist state and city, when u select state its corresponding cities should be display in another dropdown...
firstly create the table "country" add some sample data
CREATE TABLE [dbo].[country]
(
[id] [int] IDENTITY(1,1) NOT NULL,
[state] [varchar](50) NULL,
[city] [varchar](50) NULL,
}
and then in design page add two dropdowns with button
<strong>state<asp:DropDownList ID="ddlstate" runat="server" AutoPostBack="True" OnSelectedIndexChanged="ddlstate_SelectedIndexChanged">
</asp:DropDownList></strong>
<strong>city<asp:DropDownList ID="ddllcity" runat="server"
AutoPostBack="True">
</asp:DropDownList></strong>
<asp:Button ID="Button1" runat="server" OnClick="Button1_Click" Text="submit" />
then write the following coding in code separation page
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
fillddlstate();
}
}
public void fillddlstate()
{
db.myconnection();
SqlCommand cmd = new SqlCommand("select ID, state from country", db.sqlcon );
SqlDataAdapter adp = new SqlDataAdapter(cmd);
DataSet ds = new DataSet();
adp.Fill(ds );
ddlstate.DataSource = ds;
ddlstate.DataTextField = "state";
ddlstate.DataValueField = "ID";
ddlstate.DataBind();
ddlstate.Items.Insert(0, new ListItem ("--select--","0"));
}
protected void ddlstate_SelectedIndexChanged(object sender, EventArgs e)
{
db.myconnection();
SqlCommand cmd = new SqlCommand("select * from country where state='"+ddlstate.SelectedValue+"'",db.sqlcon );
SqlDataAdapter adp = new SqlDataAdapter(cmd );
DataSet ds = new DataSet();
adp.Fill(ds);
ddlcity.DataSource = ds;
ddlcity.DataTextField = "city";
ddlcity.DataValueField = "ID";
ddlcity.DataBind();
}
and u have done
njoy