<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html >
<head runat="server">
<title>ASP.NET Example</title>
</head>
<body>
<form id="form1" runat="server">
<p><asp:dropdownlist
id="DropDownList1"
runat="server"
autopostback="True">
<asp:listitem selected="True">Sales Representative</asp:listitem>
<asp:listitem>Sales Manager</asp:listitem>
<asp:listitem>Vice President, Sales</asp:listitem>
</asp:dropdownlist></p>
<asp:sqldatasource
id="SqlDataSource1"
runat="server"
connectionstring="<%$ ConnectionStrings:MyNorthwind%>"
selectcommand="SELECT LastName FROM Employees WHERE Title = @Title">
<selectparameters>
<asp:controlparameter name="Title" controlid="DropDownList1" propertyname="SelectedValue"/>
</selectparameters>
</asp:sqldatasource>
<p><asp:listbox
id="ListBox1"
runat="server"
datasourceid="SqlDataSource1"
datatextfield="LastName">
</asp:listbox></p>
</form>
</body>
</html>