Creating asp.net chart data programmatically

Suggested Videos
Part 1 - ASP.NET Chart Control
Part 2 - How to set asp.net chart control ChartType property dynamically



In Part 1 of this video series, we discussed specifying chart data declaratively in HTML. In this video we will discuss creating chart data programmatically. Please watch Part 1 and Part 2 before proceeding with this video. We will continue with the example we worked with in Parts 1 and 2.



Step 1 : From the Chart1 control on WebForm1.aspx, remove <Points> element and all the <asp:DataPoint> elements. The HTML of Chart1 control should now be as shown below. 

<asp:Chart ID="Chart1" runat="server" Width="350px">

    <Titles>

        <asp:Title Text="Total marks of students">

        </asp:Title>

    </Titles>

    <Series>

        <asp:Series Name="Series1" ChartArea="ChartArea1" ChartType="Pie">

        </asp:Series>

    </Series>

    <ChartAreas>

        <asp:ChartArea Name="ChartArea1">

            <AxisX Title="Student Name">

            </AxisX>

            <AxisY Title="Total Marks">

            </AxisY>

        </asp:ChartArea>

    </ChartAreas>

</asp:Chart>

Step 2 : Modify the code in the code-behind file as shown below. The code is commented and self explanatory.

using System;

using System.Web.UI.DataVisualization.Charting;

using System.Web.UI.WebControls;

namespace ChartsDemo

{

    public partial class WebForm1 : System.Web.UI.Page

    {

        protected void Page_Load(object sender, EventArgs e)

        {

            if (!IsPostBack)

            {

                // Call Get ChartData() method in the PageLoad event

                GetChartData();

                GetChartTypes();

            }

        }

        private void GetChartData()

        {

            // Retrieve the Series to which we want to add DataPoints

            Series series = Chart1.Series["Series1"];

            // Add X and Y values using AddXY() method

            series.Points.AddXY("Mark", 800);

            series.Points.AddXY("Steve", 900);

            series.Points.AddXY("John", 700);

            series.Points.AddXY("Mary", 900);

            series.Points.AddXY("Ben", 600);

        }

        private void GetChartTypes()

        {

            foreach (int chartType in Enum.GetValues(typeof(SeriesChartType)))

            {

                ListItem li = new ListItem(

                    Enum.GetName(typeof(SeriesChartType), chartType), chartType.ToString());

                DropDownList1.Items.Add(li);

            }

        }

        protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)

        {

            // Call Get ChartData() method when the user select a different chart type

            GetChartData();

            this.Chart1.Series["Series1"].ChartType =

                (SeriesChartType)Enum.Parse(typeof(SeriesChartType), 
                           DropDownList1.SelectedValue);

        }

    }

}

In our next video, we will discuss how to bind database data to the chart control.