Data Labels in ASP.NET MVC Chart control

22 Jul 2021 / 2 minutes to read

Data label can be added to a chart series by enabling the Visible option in the dataLabel. By default, the labels will arrange smartly without overlapping.

razor

datalabel.cs

@Html.EJS().Chart("container").Series(series =>
{
series.Type(Syncfusion.EJ2.Charts.ChartSeriesType.Column).
Marker(mr=> mr.Visible(true).DataLabel(dl=>dl.Visible(true))).
XName("x").
YName("y").
DataSource(ViewBag.dataSource). Name("Gold").Width(2).Add();
}).PrimaryXAxis(px => px.Interval(1).ValueType(Syncfusion.EJ2.Charts.ValueType.Category)).Title("Olympic Medal Counts - RIO").Render()

public ActionResult Index()
        {
            List<Data> chartData = new List<Data>
            {
           new Data{ x= "Jan", y= 3,   fill= "#498fff", text= "January" },
           new Data{ x= "Feb", y= 3.5, fill= "#ffa060", text= "February" },
           new Data{ x= "Mar", y= 7,   fill= "#ff68b6", text= "March" },
           new Data{ x= "Apr", y= 13.5,fill= "#81e2a1", text= "April" }
            };
            ViewBag.dataSource = chartData;
            return View();
        }
        public class Data
        {
            public string x;
            public double y;
            public string fill;
            public string text;
        }

Position

Using Position property, you can place the label either on Top, Middle,Bottom or Outer (outer is applicable for column and bar type series).

razor

position.cs

@Html.EJS().Chart("container").Series(series =>
                     {
                     series.Type(Syncfusion.EJ2.Charts.ChartSeriesType.Column).
                     Marker(mr=> mr.Visible(false).DataLabel(dl=>dl.Visible(true).Position(Syncfusion.EJ2.Charts.LabelPosition.Middle))).
                     XName("x").
                     YName("y").
                     DataSource(ViewBag.dataSource).
                     Name("Gold").
                     Width(2).Add();
                     }).PrimaryXAxis(px => px.Interval(1).ValueType(Syncfusion.EJ2.Charts.ValueType.Category)).Title("Olympic Medal Counts - RIO").Render()

public ActionResult Index()
        {
            List<Data> chartData = new List<Data>
            {
           new Data{ x= "Jan", y= 3,   fill= "#498fff", text= "January" },
           new Data{ x= "Feb", y= 3.5, fill= "#ffa060", text= "February" },
           new Data{ x= "Mar", y= 7,   fill= "#ff68b6", text= "March" },
           new Data{ x= "Apr", y= 13.5,fill= "#81e2a1", text= "April" }
            };
            ViewBag.dataSource = chartData;
            return View();
        }
        public class Data
        {
            public string x;
            public double y;
            public string fill;
            public string text;
        }

Note: The position Outer is applicable for column and bar type series.

Datalabel template

Label content can be formatted by using the template option. Inside the template, you can add the placeholder text ${point.x} and ${point.y} to display corresponding data points x & y value. Using Template property, you can set data label template in chart.

razor

template.cs

<div id="ControlRegion">
                  @Html.EJS().Chart("container").Series(series =>
                     {
                     series.Type(Syncfusion.EJ2.Charts.ChartSeriesType.Column).
                     Marker(mr=> mr.Visible(false).DataLabel(dl=>dl.Visible(true).Position(Syncfusion.EJ2.Charts.LabelPosition.Middle).Template("#template"))).
                     XName("x").
                     YName("y").
                     DataSource(ViewBag.dataSource).
                     Name("Gold").
                     Width(2).Add();
                     }).PrimaryXAxis(px => px.Interval(1).ValueType(Syncfusion.EJ2.Charts.ValueType.Category)).Title("Olympic Medal Counts - RIO").Render()
<script id="template">
    <div style="background:#f5f5f5; border: 1px solid black; padding: 3px 3px 3px 3px">
        <div>${point.x}</div>
        <div>${point.y}</div>
    </div>
</script>

public ActionResult Index()
        {
            List<Data> chartData = new List<Data>
            {
           new Data{ x= "Jan", y= 3,   fill= "#498fff", text= "January" },
           new Data{ x= "Feb", y= 3.5, fill= "#ffa060", text= "February" },
           new Data{ x= "Mar", y= 7,   fill= "#ff68b6", text= "March" },
           new Data{ x= "Apr", y= 13.5,fill= "#81e2a1", text= "April" }
            };
            ViewBag.dataSource = chartData;
            return View();
        }
        public class Data
        {
            public string x;
            public double y;
            public string fill;
            public string text;
        }

Text Mapping

Text from the data source can be mapped using Name property.

razor

mapping.cs

@Html.EJS().Chart("container").Series(series =>
   {
    @Html.EJS().Chart("container").Series(series =>
                     {
                     series.Type(Syncfusion.EJ2.Charts.ChartSeriesType.Column).
                     Marker(mr=> mr.Visible(false).DataLabel(dl=>dl.Visible(true).Name("text"))).
                     XName("x").
                     YName("y").
                     DataSource(ViewBag.dataSource).
                     Name("Gold").
                     Width(2).Add();
                     }).PrimaryXAxis(px => px.Interval(1).ValueType(Syncfusion.EJ2.Charts.ValueType.Category)).Title("Olympic Medal Counts - RIO").Render()

public ActionResult Index()
        {
            List<Data> chartData = new List<Data>
            {
           new Data{ x= "Jan", y= 3,   fill= "#498fff", text= "January" },
           new Data{ x= "Feb", y= 3.5, fill= "#ffa060", text= "February" },
           new Data{ x= "Mar", y= 7,   fill= "#ff68b6", text= "March" },
           new Data{ x= "Apr", y= 13.5,fill= "#81e2a1", text= "April" }
            };
            ViewBag.dataSource = chartData;
            return View();
        }
        public class Data
        {
            public string x;
            public double y;
            public string fill;
            public string text;
        }

Margin

Margin for data label can be applied to using Left, Right, Bottom and Top properties.

razor

margin.cs

@{
    var border = new { width = 2, color = "red" };
    var margin = new { left = 15, right = 15, bottom = 15, top = 15 };
 }

@Html.EJS().Chart("container").Series(series =>
                     {
                     series.Type(Syncfusion.EJ2.Charts.ChartSeriesType.Column).
                     Marker(mr=> mr.Visible(false).DataLabel(dl=>dl.Visible(true).Border(border).Margin(margin))).
                     XName("x").
                     YName("y").
                     DataSource(ViewBag.dataSource).
                     Name("Gold").
                     Width(2).Add();
                     }).PrimaryXAxis(px => px.Interval(1).ValueType(Syncfusion.EJ2.Charts.ValueType.Category)).Title("Olympic Medal Counts - RIO").Render()

public ActionResult Index()
        {
            List<Data> chartData = new List<Data>
            {
           new Data{ x= "Jan", y= 3,   fill= "#498fff", text= "January" },
           new Data{ x= "Feb", y= 3.5, fill= "#ffa060", text= "February" },
           new Data{ x= "Mar", y= 7,   fill= "#ff68b6", text= "March" },
           new Data{ x= "Apr", y= 13.5,fill= "#81e2a1", text= "April" }
            };
            ViewBag.dataSource = chartData;
            return View();
        }
        public class Data
        {
            public string x;
            public double y;
            public string fill;
            public string text;
        }

Customization

stroke and border of data label can be customized using Fill and Border properties. Rounded corners can be customized using Rx and Ry properties.

razor

custom.cs

@{
    var border = new { width = 2, color = "red" };
    var margin = new { left = 15, right = 15, bottom = 15, top = 15 };
 }
 @Html.EJS().Chart("container").Series(series =>
                     {
                     series.Type(Syncfusion.EJ2.Charts.ChartSeriesType.Column).
                     Marker(mr=> mr.Visible(false).DataLabel(dl=>dl.Visible(true).Border(border).Name("text").Rx(10).Ry(10).Fill("skyblue"))).
                     XName("x").
                     YName("y").
                     DataSource(ViewBag.dataSource).
                     Name("Gold").
                     Width(2).Add();
                     }).PrimaryXAxis(px => px.Interval(1).ValueType(Syncfusion.EJ2.Charts.ValueType.Category)).Title("Olympic Medal Counts - RIO").Render()

public ActionResult Index()
        {
            List<Data> chartData = new List<Data>
            {
           new Data{ x= "Jan", y= 3,   fill= "#498fff", text= "January" },
           new Data{ x= "Feb", y= 3.5, fill= "#ffa060", text= "February" },
           new Data{ x= "Mar", y= 7,   fill= "#ff68b6", text= "March" },
           new Data{ x= "Apr", y= 13.5,fill= "#81e2a1", text= "April" }
            };
            ViewBag.dataSource = chartData;
            return View();
        }
        public class Data
        {
            public string x;
            public double y;
            public string fill;
            public string text;
        }

Note: Rx and Ry properties requires Border values not to be null.

Customizing Specific Point

You can also customize the specific marker and label using PointRender and TextRender event. PointRender event allows you to change the shape, color and border for a point, whereas the TextRender event allows you to change the text for the point.

razor

custom-point.cs

@Html.EJS().Chart("container").TextRender("textRender").PointRender("pointRender").Series(series =>
                     {
                     series.Type(Syncfusion.EJ2.Charts.ChartSeriesType.Column).
                     Marker(mr=> mr.Visible(false).DataLabel(dl=>dl.Visible(true))).
                     XName("x").
                     YName("y").
                     DataSource(ViewBag.dataSource).
                     Name("Gold").
                     Width(2).Add();
                     }).PrimaryXAxis(px => px.Interval(1).ValueType(Syncfusion.EJ2.Charts.ValueType.Category)).Title("Olympic Medal Counts - RIO").Render()
<script>
pointRender = function (args) {
        if (args.point.index === 2) {
            args.fill = 'red'
        }
    },
textRender = function (args) {
            if (args.point.index === 2) {
                args.text = 'Maximum Temperature';
                args.color = 'red';
            }
            else {
                args.cancel = true;
            }
        }
</script>

public ActionResult Index()
        {
            List<Data> chartData = new List<Data>
            {
           new Data{ x= "Jan", y= 3,   fill= "#498fff", text= "January" },
           new Data{ x= "Feb", y= 3.5, fill= "#ffa060", text= "February" },
           new Data{ x= "Mar", y= 7,   fill= "#ff68b6", text= "March" },
           new Data{ x= "Apr", y= 13.5,fill= "#81e2a1", text= "April" }
            };
            ViewBag.dataSource = chartData;
            return View();
        }
        public class Data
        {
            public string x;
            public double y;
            public string fill;
            public string text;
        }

Contents

Position
Datalabel template
Text Mapping
Margin
Customization
Customizing Specific Point

Contents

Position
Datalabel template
Text Mapping
Margin
Customization
Customizing Specific Point

Please provide additional information

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