How to put markers on the x-axis of a chart line C #

I would like to know how to leave markers (such as a ball) on X-axes at each point in the chart. Currently the graphic looks like this:

Iwantedeverymonthtohaveaballpointnodecorrespondingtothevalueandnotthattherewasonlyoneline,Iwouldlikeittolooksomethinglikethis:

WhichpropertydoIneedtochange?

Followthecodeinthechart:

<asp:ChartID="graficoLinhaVendas" runat="server" Width="750px" >
                                        <Series>
                                            <asp:Series Name="graficoLinhaVendas" ChartType="Spline" IsXValueIndexed="True" BorderWidth="2" YValuesPerPoint="2"></asp:Series>
                                        </Series>
                                        <ChartAreas>
                                            <asp:ChartArea Name="ChartArea1" AlignmentOrientation="All" BackColor="Transparent" BackImageTransparentColor="Transparent" BorderColor="Transparent" ShadowColor="DimGray">
                                                <AxisY InterlacedColor="WhiteSmoke" IsInterlaced="True">
                                                    <MajorGrid LineColor="WhiteSmoke" />
                                                </AxisY>
                                                <AxisX>
                                                    <MajorGrid IntervalType="Auto" LineColor="Gainsboro" />
                                                    <MajorTickMark LineWidth="10" Size="10" TickMarkStyle="None" />
                                                </AxisX>
                                                <AxisX2 LineColor="Silver" LineWidth="10">
                                                </AxisX2>
                                                <Area3DStyle Inclination="10" IsClustered="True" IsRightAngleAxes="False" PointDepth="0" PointGapDepth="0" Rotation="50" WallWidth="10" />
                                            </asp:ChartArea>
                                        </ChartAreas>
                                    </asp:Chart>


public void MontarGraficoLinha()
    {
        graficoLinhaVendas.Series["graficoLinhaVendas"].Points.AddXY("Janeiro", 1000);
        graficoLinhaVendas.Series["graficoLinhaVendas"].Points.AddXY("Fevereiro", 1465);
        graficoLinhaVendas.Series["graficoLinhaVendas"].Points.AddXY("Março", 845);
        graficoLinhaVendas.Series["graficoLinhaVendas"].Points.AddXY("Abril", 1173);
        graficoLinhaVendas.Series["graficoLinhaVendas"].Points.AddXY("Maio", 1500);
    }