ChartDataLabel class

Represents data label on a chart point or trendline.

public class ChartDataLabel


Name Description
Index { get; } Specifies the index of the containing element. This index shall determine which of the parent’s children collection this element applies to. Default value is 0.
IsHidden { get; set; } Gets/sets a flag indicating whether this label is hidden. The default value is false.
IsVisible { get; } Returns true if this data label has something to display.
NumberFormat { get; } Returns number format of the parent element.
Separator { get; set; } Gets or sets string separator used for the data labels on a chart. The default is a comma, except for pie charts showing only category name and percentage, when a line break shall be used instead.
ShowBubbleSize { get; set; } Allows to specify if bubble size is to be displayed for the data labels on a chart. Applies only to Bubble charts. Default value is false.
ShowCategoryName { get; set; } Allows to specify if category name is to be displayed for the data labels on a chart. Default value is false.
ShowDataLabelsRange { get; set; } Allows to specify if values from data labels range to be displayed in the data labels. Default value is false.
ShowLeaderLines { get; set; } Allows to specify if data label leader lines need be shown. Default value is false.
ShowLegendKey { get; set; } Allows to specify if legend key is to be displayed for the data labels on a chart. Default value is false.
ShowPercentage { get; set; } Allows to specify if percentage value is to be displayed for the data labels on a chart. Default value is false.
ShowSeriesName { get; set; } Returns or sets a Boolean to indicate the series name display behavior for the data labels on a chart. True to show the series name. False to hide. By default false.
ShowValue { get; set; } Allows to specify if values are to be displayed in the data labels. Default value is false.


Name Description
ClearFormat() Clears format of this data label. The properties are set to the default values defined in the parent data label collection.


On a series, the ChartDataLabel object is a member of the ChartDataLabelCollection. The ChartDataLabelCollection contains a ChartDataLabel object for each point.


Shows how to apply labels to data points in a line chart.

public void DataLabels()
    Document doc = new Document();
    DocumentBuilder builder = new DocumentBuilder(doc);

    Shape chartShape = builder.InsertChart(ChartType.Line, 400, 300);
    Chart chart = chartShape.Chart;

    Assert.AreEqual(3, chart.Series.Count);
    Assert.AreEqual("Series 1", chart.Series[0].Name);
    Assert.AreEqual("Series 2", chart.Series[1].Name);
    Assert.AreEqual("Series 3", chart.Series[2].Name);

    // Apply data labels to every series in the chart.
    // These labels will appear next to each data point in the graph and display its value.
    foreach (ChartSeries series in chart.Series)
        ApplyDataLabels(series, 4, "000.0", ", ");
        Assert.AreEqual(4, series.DataLabels.Count);

    // Change the separator string for every data label in a series.
    using (IEnumerator<ChartDataLabel> enumerator = chart.Series[0].DataLabels.GetEnumerator())
        while (enumerator.MoveNext())
            Assert.AreEqual(", ", enumerator.Current.Separator);
            enumerator.Current.Separator = " & ";

    // For a cleaner looking graph, we can remove data labels individually.

    // We can also strip an entire series of its data labels at once.

    doc.Save(ArtifactsDir + "Charts.DataLabels.docx");

/// <summary>
/// Apply data labels with custom number format and separator to several data points in a series.
/// </summary>
private static void ApplyDataLabels(ChartSeries series, int labelsCount, string numberFormat, string separator)
    for (int i = 0; i < labelsCount; i++)
        series.HasDataLabels = true;


        series.DataLabels[i].ShowCategoryName = true;
        series.DataLabels[i].ShowSeriesName = true;
        series.DataLabels[i].ShowValue = true;
        series.DataLabels[i].ShowLeaderLines = true;
        series.DataLabels[i].ShowLegendKey = true;
        series.DataLabels[i].ShowPercentage = false;
        series.DataLabels[i].IsHidden = false;

        series.DataLabels[i].NumberFormat.FormatCode = numberFormat;
        series.DataLabels[i].Separator = separator;


See Also