Introduction & Demonstration
The DropDownList control enables us to display a list of options while requiring
a minimum of screen real estate. A user can select only one option at a time
when using this control.
The page given below illustrates how we can use the DropDownList control to
display all the product titles from the PRO_LIST database table.
<%@ 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">
<script runat="server">
Protected Sub
btnSubmit_Click(ByVal sender
As Object,
ByVal e As
EventArgs)
lblProducts.Text = ddlProducts.SelectedItem.Text
End Sub
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:DropDownList
id="ddlProducts"
DataSourceID="SqlDataSource1"
DataTextField="TITLE"
DataValueField="ID"
Runat="server" />
<asp:Button
id="btnSubmit"
Text="Submit"
OnClick="btnSubmit_Click"
Runat="server" />
<hr />
<asp:Label
id="lblProducts"
Runat="server" />
<asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$
ConnectionStrings:DatabaseConnectionString1 %>"
ProviderName="<%$
ConnectionStrings:DatabaseConnectionString1.ProviderName
%>"
SelectCommand="SELECT
[ID], [TITLE] FROM [PRO_LIST]"></asp:SqlDataSource>
</div>
</form>
</body>
</html>
The DropDownList control renders an HTML <select> tag. One problem with the HTML
<select> tag is that it has an infinite z index. In other words, we can't place
other objects, such as an absolutely positioned <div> tag, in front of a
DropDownList control in a page.
HAVE A GREAT CODING!