How to: Individually Customize Axis Labels

Nov 17, 2021
2 minutes to read

Apart from the capability to customize the overall appearance of axis labels, you can obtain individual axis labels at runtime. Then, it’s possible to apply all the options available for axis labels to them, individually. You can apply different formatting to axis labels based on some criteria (for example, an axis value threshold).

For this, the special ChartControl.CustomDrawAxisLabel event is introduced. Handle it to obtain axis labels.

Note

For the WebChartControl you should handle its WebChartControl.CustomDrawAxisLabel event to implement this task.

The following code demonstrates one possible implementation of this capability.

View Example

C#
VB.NET

private void chartControl1_CustomDrawAxisLabel(object sender, CustomDrawAxisLabelEventArgs e) {
    AxisBase axis = e.Item.Axis;
    if (axis is AxisY || axis is AxisY3D || axis is RadarAxisY) {
        double axisValue = (double)e.Item.AxisValue;
        if (axisValue < 0)
            // Customize the axis label's color.
            e.Item.TextColor = Color.Red;
        else if (axisValue > 0) {
            // Customize the axis label's text and color.
            e.Item.Text = "+" + e.Item.Text;
            e.Item.TextColor = Color.Green;
        }
        else if (axisValue == 0) {
            // Hide the axis labels.
            e.Item.Text = "";
        }
    }
}

Private Sub chartControl1_CustomDrawAxisLabel(ByVal sender As Object, ByVal e As CustomDrawAxisLabelEventArgs)
    Dim axis As AxisBase = e.Item.Axis
    If TypeOf axis Is AxisY OrElse TypeOf axis Is AxisY3D OrElse TypeOf axis Is RadarAxisY Then
        Dim axisValue As Double = CDbl(e.Item.AxisValue)
        If axisValue < 0 Then
            ' Customize the axis label's color.
            e.Item.TextColor = Color.Red
        ElseIf axisValue > 0 Then
            ' Customize the axis label's text and color.
            e.Item.Text = "+" & e.Item.Text
            e.Item.TextColor = Color.Green
        ElseIf axisValue = 0 Then
            ' Hide the axis labels.
            e.Item.Text = ""
        End If
    End If
End Sub

The following image shows the resulting Chart: