Generally while doing registration in a
website. When we choose any city dropdown list, its related states, country and
zip code bind in respective dropdownlist.and textboxes.
Default.aspx code
<%@
Page
Language="VB"
AutoEventWireup="false"
CodeFile="Default.aspx.vb"
Inherits="_Default"
%>
<!DOCTYPE
html PUBLIC
"-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html
xmlns="http://www.w3.org/1999/xhtml">
<head
runat="server">
<title>Untitled
Page</title>
</head>
<body>
<form
id="form1"
runat="server">
<div>
</div>
<asp:Label
ID="Label1"
runat="server"
Text="Choose city"
Width="100px"></asp:Label>
<asp:DropDownList
ID="DropDownList1"
runat="server"
AutoPostBack="True">
<asp:ListItem>select</asp:ListItem>
</asp:DropDownList>
<br
/>
<asp:Label
ID="Label2"
runat="server"
Text="State"
Width="100px"></asp:Label>
<asp:DropDownList
ID="DropDownList2"
runat="server">
</asp:DropDownList>
<br
/>
<asp:Label
ID="Label3"
runat="server"
Text="Country"
Width="100px"></asp:Label>
<asp:DropDownList
ID="DropDownList3"
runat="server">
</asp:DropDownList><br
/>
<asp:Label
ID="Label4"
runat="server"
Text="Zipcode"
Width="100px"></asp:Label>
<asp:TextBox
ID="TextBox1"
runat="server"></asp:TextBox>
</form>
</body>
</html>
Default.aspx.vb code
Imports
System.Data
Imports
System.Data.SqlClient
Partial
Class _Default
Inherits System.Web.UI.Page
Dim strConnString
As String =
System.Configuration.ConfigurationManager.ConnectionStrings.Item("ConnectionString").ToString()
Dim con As
New SqlConnection(strConnString)
Dim str As
String
Dim com
As SqlCommand
Protected Sub
Page_Load(ByVal sender
As Object,
ByVal e As
System.EventArgs) Handles
Me.Load
If Not
IsPostBack Then
con.Open()
str = "select * from area"
com = New SqlCommand(str,
con)
Dim reader
As SqlDataReader = com.ExecuteReader
While reader.Read
DropDownList1.Items.Add(reader("city"))
End
While
reader.Close()
con.Close()
End If
DropDownList2.Items.Clear()
DropDownList3.Items.Clear()
TextBox1.Text = ""
End Sub
Protected Sub
DropDownList1_SelectedIndexChanged(ByVal
sender As Object,
ByVal e As
System.EventArgs) Handles
DropDownList1.SelectedIndexChanged
con.Open()
str = "select * from area where
city='" & DropDownList1.SelectedValue &
"'"
com = New SqlCommand(str, con)
Dim reader
As SqlDataReader = com.ExecuteReader
Do While
reader.Read
DropDownList2.Items.Add(reader("state"))
DropDownList3.Items.Add(reader("country"))
TextBox1.Text = reader("stdcode")
Loop
reader.Close()
con.Close()
End Sub
End
Class
Output
![Output-in-windows8.gif]()