:master: io non utilizzo mai i datasource. Comunque, questo di sotto funziona:

codice:
<%@ Page Language="VB" AutoEventWireup="false" CodeFile="a.aspx.vb" Inherits="prove_a" %>

<!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></title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:AccessDataSource ID="AccessDataSource1" runat="server" DataFile="C:\dati\test\test.mdb" SelectCommand="select testo from campi where id=4"></asp:AccessDataSource>
        <asp:ListView ID="ListView1" runat="server" DataMember="DefaultView" DataSourceID="AccessDataSource1">
            <LayoutTemplate>
                <asp:PlaceHolder runat="server" id="itemPlaceholder"></asp:PlaceHolder>
            </LayoutTemplate>
            <ItemTemplate>
                <span><%#Eval("testo")%></span>
            </ItemTemplate>
        </asp:ListView>
    </div>
    </form>
</body>
</html>