Add Annotations using ASP.NET

FusionCharts.NET

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Annotations are graphical elements (different types of shapes, custom text, and so on) that you can render on your chart to make it more informative while making it visually appealing.

In this article, we'll create a Spline chart and add annotations to highlight a particular anchor along with text using the FusionCharts ASP.NET C# & VB wrapper. A sample chart is shown below:

FusionCharts will load here..
{
    "chart": {
        "caption": "Average Monthly Temperature in Texas",
        "yAxisName": "Average Monthly Temperature",
        "anchorradius": "5",
        "plotToolText": "Average temperature in $label is <b>$dataValue</b>",
        "showHoverEffect": "1",
        "showvalues": "0",
        "numberSuffix": "°C",
        "theme": "fusion",
        "anchorBgColor": "#72D7B2",
        "paletteColors": "#72D7B2"
    },
    "annotations": {
        "groups": [
            {
                "id": "anchor-highlight",
                "items": [
                    {
                        "id": "high-star",
                        "type": "circle",
                        "x": "$dataset.0.set.7.x",
                        "y": "$dataset.0.set.7.y",
                        "radius": "12",
                        "color": "#cc0000",
                        "border": "2",
                        "borderColor": "#0075c2"
                    },
                    {
                        "id": "label",
                        "type": "text",
                        "text": "Hottest Month",
                        "fillcolor": "#0075c2",
                        "rotate": "90",
                        "x": "$dataset.0.set.7.x+75",
                        "y": "$dataset.0.set.7.y-2"
                    }
                ]
            }
        ]
    },
    "data": [
        {
            "label": "Jan",
            "value": "1"
        },
        {
            "label": "Feb",
            "value": "5"
        },
        {
            "label": "Mar",
            "value": "10"
        },
        {
            "label": "Apr",
            "value": "12"
        },
        {
            "label": "May",
            "value": "14"
        },
        {
            "label": "Jun",
            "value": "16"
        },
        {
            "label": "Jul",
            "value": "20"
        },
        {
            "label": "Aug",
            "value": "22"
        },
        {
            "label": "Sep",
            "value": "20"
        },
        {
            "label": "Oct",
            "value": "16"
        },
        {
            "label": "Nov",
            "value": "7"
        },
        {
            "label": "Dec",
            "value": "2"
        }
    ]
}

The consolidated code for the above chart is shown below:


using System;
using FusionCharts.Charts;

public partial class Pages_ChartAnnotations: System.Web.UI.Page {
protected void Page_Load(object sender, EventArgs e) {
//json data in string format
string jsonData = "{'chart':{'caption':'Average Monthly Temperature in Texas','yAxisName':'Average Monthly Temperature','anchorradius':'5','plotToolText':'Average temperature in $label is $dataValue','showHoverEffect':'1','showvalues':'0','numberSuffix':'°C','theme':'fusion','anchorBgColor':'#72D7B2','paletteColors':'#72D7B2'},'annotations':{'groups':[{'id':'anchor-highlight','items':[{'id':'high-star','type':'circle','x':'$dataset.0.set.7.x','y':'$dataset.0.set.7.y','radius':'12','color':'#cc0000','border':'2','borderColor':'#0075c2'},{'id':'label','type':'text','text':'Hottest Month','fillcolor':'#0075c2','rotate':'90','x':'$dataset.0.set.7.x+75','y':'$dataset.0.set.7.y-2'}]}]},'data':[{'label':'Jan','value':'1'},{'label':'Feb','value':'5'},{'label':'Mar','value':'10'},{'label':'Apr','value':'12'},{'label':'May','value':'14'},{'label':'Jun','value':'16'},{'label':'Jul','value':'20'},{'label':'Aug','value':'22'},{'label':'Sep','value':'20'},{'label':'Oct','value':'16'},{'label':'Nov','value':'7'},{'label':'Dec','value':'2'}]}";
// create chart instance
// parameter
// chart type, chart id, chart width, chart height, data format, data source
Chart spline = new Chart("spline", "spline_chart", "700", "400", "json", jsonData);
//render chart
Literal1.Text = spline.Render();
}
}



Imports FusionCharts.Charts
Partial Class Pages_ChartAnnotation
Inherits System.Web.UI.Page
Protected Sub Page_Load(sender As Object, e As EventArgs) Handles MyBase.Load store chart  data url as  string
Dim jsonData As String
jsonData = "{'chart':{'caption':'Average Monthly Temperature in Texas','yAxisName':'Average Monthly Temperature','anchorradius':'5','plotToolText':'Average temperature in $label is $dataValue','showHoverEffect':'1','showvalues':'0','numberSuffix':'°C','theme':'fusion','anchorBgColor':'#72D7B2','paletteColors':'#72D7B2'},'annotations':{'groups':[{'id':'anchor-highlight','items':[{'id':'high-star','type':'circle','x':'$dataset.0.set.7.x','y':'$dataset.0.set.7.y','radius':'12','color':'#cc0000','border':'2','borderColor':'#0075c2'},{'id':'label','type':'text','text':'Hottest Month','fillcolor':'#0075c2','rotate':'90','x':'$dataset.0.set.7.x+75','y':'$dataset.0.set.7.y-2'}]}]},'data':[{'label':'Jan','value':'1'},{'label':'Feb','value':'5'},{'label':'Mar','value':'10'},{'label':'Apr','value':'12'},{'label':'May','value':'14'},{'label':'Jun','value':'16'},{'label':'Jul','value':'20'},{'label':'Aug','value':'22'},{'label':'Sep','value':'20'},{'label':'Oct','value':'16'},{'label':'Nov','value':'7'},{'label':'Dec','value':'2'}]}"
'create gauge instance
'chart type, chart id, width, height, data format, data source as url
Dim spline As New Chart("spline", "spline_chart", "700", "400", "json", jsonData)
'render gauge
Literal1.Text = spline.Render()
End Sub
End Class

The HTML template for aspx file is shown below:


<%@ Page Language="C#" AutoEventWireup="true" CodeFile="ChartAnnotations.aspx.cs" Inherits="Pages_ChartAnnotations" %>

<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">

<head runat="server">
<title>FusionCharts | Using Annotations On Chart</title>
</head>

<body style="font-family: Helvetica Neue, Arial; font-size: 16px;">
<script type="text/javascript" src="//cdn.fusioncharts.com/fusioncharts/latest/fusioncharts.js"></script>
<script type="text/javascript" src="//cdn.fusioncharts.com/fusioncharts/latest/themes/fusioncharts.theme.fusion.js"></script>
<form id="form1" runat="server">
<h3>Using Annotations On Chart</h3>
<div>
<asp:Literal ID="Literal1" runat="server"></asp:Literal>
</div>
<div><span>
<asp:HyperLink id="hyperlink1" NavigateUrl="../Default.aspx" Text="Go Back" runat="server" /></span></div>
</form>
</body>

</html>



<%@ Page Language="VB" AutoEventWireup="true" CodeFile="ChartAnnotations.aspx.vb" Inherits="Pages_ChartAnnotations" %>

<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">

<head runat="server">
<title>FusionCharts | Using Annotations On Chart</title>
</hea>

<body style="font-family: Helvetica Neue, Arial; font-size: 16px;">
<script type="text/javascript" src="//cdn.fusioncharts.com/fusioncharts/latest/fusioncharts.js"></script>
<script type="text/javascript" src="//cdn.fusioncharts.com/fusioncharts/latest/themes/fusioncharts.theme.fusion.js"></script>
<form id="form1" runat="server">
<h3>Using Annotations On Chart</h3>
<div>
<asp:Literal ID="Literal1" runat="server"></asp:Literal>
</div>
<div><span>
<asp:HyperLink id="hyperlink1" NavigateUrl="../Default.aspx" Text="Go Back" runat="server" /></span></div>
</form>
</body>

</html>


Apart from the usual boilerplate, the sample C#/VB code provided above corresponds to the following tasks:

  1. Import and resolve the dependencies like System, and FusionCharts.Charts.

  2. Define a class Pages_ChartAnnotations inherited from System.Web.UI.Page. Correspondingly, in the .aspx file, Pages_ChartAnnotations is inherited.

  3. Within the class Pages_ChartAnnotations, define Page_Load():

    • Declare a string jsonData and use it to assign the chart configuration as a JSON string.

    • Create an instance of Chart (defined within FusionCharts.Charts), and assign it the necessary attributes of a Spline chart. See the source code comments for the attributes used. Of particular importance is the attribute chartType, which in this case is spline. Find the complete list of chart types with their respective alias here.

    • Render the chart using the [instanceName].Render() method. Correspondingly, in the .aspx file, include the necessary chart and theme libraries modules using the <script> tags, like fusioncharts.js, fusioncharts.theme.fusion.js, and within a <form><div>, render the chart.

Refer to Spline chart for more information on the configuration and data for this chart type.