questo è un piccolo esempio.

1) creo un sito web vuoto
2) creo una pagina

codice:
<%@ 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></title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:Chart ID="Chart1" runat="server">
            <Titles>
                <asp:Title Text="Ore lavorate divise per cliente">
                </asp:Title>
            </Titles>
            <Series>
                <asp:Series Name="Series1" Legend="legenda1" ChartArea="ChartArea1" ChartType="Doughnut" YValueType="Double" IsValueShownAsLabel="true">
                </asp:Series>
            </Series>
            <ChartAreas>
                <asp:ChartArea Name="ChartArea1">
                    <Area3DStyle LightStyle="Realistic" Enable3D="true" />
                </asp:ChartArea>
            </ChartAreas>
            <Legends>
                <asp:Legend Name="legenda1" Title="Clienti:">
                </asp:Legend>
            </Legends>
        </asp:Chart>
    </div>
    </form>
</body>
</html>
codice:
Option Strict On
Imports System.Web.UI.DataVisualization.Charting

Partial Class _Default
    Inherits System.Web.UI.Page

    Protected Sub Page_Load(sender As Object, e As System.EventArgs) Handles Me.Load
        If Not Me.IsPostBack Then
            CreaGrafico()
        End If
    End Sub

    Private Sub CreaGrafico()
        Dim c As Chart = Me.Chart1
        Dim s As Series = c.Series(0)

        Dim p As DataPoint = Nothing

        p = New DataPoint(1, 1) : s.Points.Add(p)
        p = New DataPoint(2, 2) : s.Points.Add(p)

    End Sub

End Class
web.config
codice:
<?xml version="1.0"?>
<!--
  Per ulteriori informazioni su come configurare l'applicazione ASP.NET, visitare il sito Web all'indirizzo
  http://go.microsoft.com/fwlink/?LinkId=169433
  -->
<configuration>
    <appSettings>
        <add key="ChartImageHandler" value="storage=memory;deleteAfterServicing=true;" />
    </appSettings>
    <system.webServer>
        <validation validateIntegratedModeConfiguration="false" />
        <handlers>
            <remove name="ChartImageHandler" />
            <add name="ChartImageHandler" preCondition="integratedMode" verb="GET,HEAD,POST"
              path="ChartImg.axd" type="System.Web.UI.DataVisualization.Charting.ChartHttpHandler, System.Web.DataVisualization, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" />
        </handlers>
    </system.webServer>
    <system.web>
        <httpHandlers>
            <add path="ChartImg.axd" verb="GET,HEAD,POST" type="System.Web.UI.DataVisualization.Charting.ChartHttpHandler, System.Web.DataVisualization, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"
              validate="false" />
        </httpHandlers>
        <pages>
            <controls>
                <add tagPrefix="asp" namespace="System.Web.UI.DataVisualization.Charting" assembly="System.Web.DataVisualization, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" />
            </controls>
        </pages>
        <compilation debug="false" strict="false" explicit="true" targetFramework="4.0">
            <assemblies>
                <add assembly="System.Web.DataVisualization, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
            </assemblies>
        </compilation>
    </system.web>
</configuration>