学习了Chart控件的初步使用方法，生成柱形图和饼图。

   <asp:Chart ID="Chart1" runat="server" Width="553px" Height="403px">

            <Series>

                <asp:Series LegendText="得票数" Name="Series1" IsValueShownAsLabel="True" XValueMember="选择项"

                    YValueMembers="数量" Legend="Legend1" Color="Red" Font="Microsoft Sans Serif, 12pt"

                    LabelForeColor="Green">

                </asp:Series>

                <asp:Series ChartArea="ChartArea2" ChartType="Pie" Legend="Legend2" 

                    Name="Series2" IsValueShownAsLabel="True" XValueMember="选择项"

                    YValueMembers="数量" XValueType="String">

                </asp:Series>

            </Series>

            <ChartAreas>

                <asp:ChartArea Name="ChartArea1">

                    <AxisY Title="得票数">

                        <LabelStyle ForeColor="Blue" />

                    </AxisY>

                    <AxisX Title="课程">

                        <MajorGrid LineColor="Yellow" />

                        <%--线条颜色--%>

                    </AxisX>

                </asp:ChartArea>

                <asp:ChartArea Name="ChartArea2">

                    <AxisY Title="得票数">

                        <LabelStyle ForeColor="Blue" />

                    </AxisY>

                    <AxisX Title="课程">

                        <MajorGrid LineColor="Yellow" />

                        <%--线条颜色--%>

                    </AxisX>

                </asp:ChartArea>

            </ChartAreas>

            <Legends>

                <asp:Legend Name="Legend1">

                </asp:Legend>

                <asp:Legend Name="Legend2">

                <Position X="80" Y="50" Height="20" Width="30" />

                </asp:Legend>

            </Legends>

            <Titles>

                <asp:Title Name="Title1" Text="投票结果">

                </asp:Title>

            </Titles>

        </asp:Chart>
后台代码：

        protected void Page_Load(object sender, EventArgs e)

        {

            if (!IsPostBack)

            {

                Chart1.DataSource = GetTable();
//#XVAL表示数据点的X值，#YVAL表示数据点的Y值

                Chart1.Series[1].Label = "课程:#VALX，得票数：#VALY";
                //显示在饼图外面

                Chart1.Series[1].CustomProperties = "PieLabelStyle=Outside";

                Chart1.Series[1].LabelToolTip = "#VALX: #VALY";
//自定义图例

                Chart1.Series[1].LegendText = "#VALX";

                

            }

        }

        public DataTable GetTable()

        {

            string collectionstring = @"Data Source=.\sqlexpress;Initial Catalog=OnlineVoteDB;User ID=sa;Pwd=xx;Persist Security Info=True;"; 

            SqlConnection conn = new SqlConnection(collectionstring);

            SqlDataAdapter sad = new SqlDataAdapter("select name as 选择项,votecount as 数量 from [Items] where [SubjectID]=13 ", conn);

            DataSet ds = new DataSet();

            sad.Fill(ds, "table"); conn.Close();

            return ds.Tables[0];

        }

    }
效果：