Empty Points

• Jul 26, 2019
• 6 minutes to read

Empty points are points with undefined Values. This document describes how the Chart Control processes empty points.

The Chart displays empty points as breaks in the Line or Area series views, and missing points or bars in other series view types.

Line View

Spline Area View

Step Line 3D View

Bar View

Point View

The following table contains data for the charts above:

Date	Politics	Entertainment	Travel
01-Nov-16	65	56	45
02-Nov-16	78	45	40
03-Nov-16	95	70	56
04-Nov-16	110	82	47
05-Nov-16	108	80	38
06-Nov-16	52	20	31
07-Nov-16	46	10	27
08-Nov-16	70		27
09-Nov-16	86		42
10-Nov-16	92	65
11-Nov-16	108	45	37
12-Nov-16	115	56	21
13-Nov-16	75	10	10
14-Nov-16	65	0	5

Note

19.1 Demo Center: Launch the Empty Points demo

To make a point empty, do one of the following:

• leave a point’s value blank if you use the Chart Designer to add points to a series.

  

• use the SeriesPoint‘s class constructors that take only an argument as a parameter if you add points to a series in code.

  C#

  using DevExpress.XtraCharts;
  using System;
  using System.Collections.Generic;
  using System.Windows.Forms;
  namespace EmptyPointRepsentation {
      public partial class Form1 : Form {
          ChartControl chart { get { return chartControl1; } }
          public Form1() {
              InitializeComponent();
              Series series = new Series();
              // The following line adds an empty series point to a series.
              series.Points.Add(new SeriesPoint(new DateTime(2019,1,1)));
              chart.Series.Add(series);
          }
      }
  }
  

  VB.NET

  Imports DevExpress.XtraCharts
  Imports System
  Imports System.Collections.Generic
  Imports System.Windows.Forms
  Namespace EmptyPointRepsentation
      Public Partial Class Form1
          Inherits Form
  
          Private ReadOnly Property chart As ChartControl
              Get
                  Return chartControl1
              End Get
          End Property
          Public Sub New()
              InitializeComponent()
              Dim series As Series = New Series()
              series.Points.Add(New SeriesPoint(New DateTime(2019, 1, 1)))
              chart.Series.Add(series)
          End Sub
      End Class
  End Namespace
  

• or set a data point’s value to Double.NaN in a data source.

  C#

  using DevExpress.XtraCharts;
  using System;
  using System.Collections.Generic;
  using System.Windows.Forms;
  
  namespace EmptyPointRepsentation {
      public partial class Form1 : Form {
          ChartControl chart { get { return chartControl1; } }
          public Form1() {
              InitializeComponent();
          }
          private void OnFormLoad(object sender, EventArgs e) {
              chart.DataSource = DataPoint.GetPoints();
              Series series1 = new Series("Politics", ViewType.Line);
              series1.SetDataMembers("Date", "Politics");
              Series series2 = new Series("Entertainment", ViewType.Line);
              series2.SetDataMembers("Date", "Entertainment");
              Series series3 = new Series("Travel", ViewType.Line);
              series3.SetDataMembers("Date", "Travel");
              chart.Series.AddRange(new Series[] { series1, series2, series3 });
          }
      }
      public class DataPoint {
          public DateTime Date { get; set; }
          public Double Politics { get; set; }
          public Double Entertainment { get; set; }
          public Double Travel { get; set; }
          public static List<DataPoint> GetPoints() {
              return new List<DataPoint> {
                      new DataPoint { Date = new DateTime(2016,11,1), Politics = 65,   Entertainment = 56, Travel = 45 },
                      new DataPoint { Date = new DateTime(2016,11,2), Politics = 78,   Entertainment = 45, Travel = 40 },
                      new DataPoint { Date = new DateTime(2016,11,3), Politics = 95,   Entertainment = 70, Travel = 56 },
                      new DataPoint { Date = new DateTime(2016,11,4), Politics = 110,  Entertainment = 82, Travel = 47 },
                      new DataPoint { Date = new DateTime(2016,11,5), Politics = 108,  Entertainment = 80, Travel = 38 },
                      new DataPoint { Date = new DateTime(2016,11,6), Politics = 52,   Entertainment = 20, Travel = 31 },
                      new DataPoint { Date = new DateTime(2016,11,7), Politics = 46,   Entertainment = 10, Travel = 27 },
                      new DataPoint { Date = new DateTime(2016,11,8), Politics = 70,   Entertainment = Double.NaN, Travel = 27 },
                      new DataPoint { Date = new DateTime(2016,11,9), Politics = 86,   Entertainment = Double.NaN, Travel = 42 },
                      new DataPoint { Date = new DateTime(2016,11,10), Politics = 92,  Entertainment = 65, Travel = Double.NaN},
                      new DataPoint { Date = new DateTime(2016,11,11), Politics = 105, Entertainment = 45, Travel = 37 },
                      new DataPoint { Date = new DateTime(2016,11,12), Politics = 115, Entertainment = 56, Travel = 21 },
                      new DataPoint { Date = new DateTime(2016,11,13), Politics = 75,  Entertainment = 10, Travel = 10 },
                      new DataPoint { Date = new DateTime(2016,11,14), Politics = 65,  Entertainment = 0 , Travel = 5  }
                  };
          }
      }
  }
  

  VB.NET

  Imports DevExpress.XtraCharts
  Imports System
  Imports System.Collections.Generic
  Imports System.Windows.Forms
  
  Namespace EmptyPointRepsentation
      Public Partial Class Form1
          Inherits Form
  
          Private ReadOnly Property chart As ChartControl
              Get
                  Return chartControl1
              End Get
          End Property
  
          Public Sub New()
              InitializeComponent()
          End Sub
  
          Private Sub OnFormLoad(ByVal sender As Object, ByVal e As EventArgs)
              chart.DataSource = DataPoint.GetPoints()
              Dim series1 As Series = New Series("Politics", ViewType.Line)
              series1.SetDataMembers("Date", "Politics")
              Dim series2 As Series = New Series("Entertainment", ViewType.Line)
              series2.SetDataMembers("Date", "Entertainment")
              Dim series3 As Series = New Series("Travel", ViewType.Line)
              series3.SetDataMembers("Date", "Travel")
              chart.Series.AddRange(New Series() {series1, series2, series3})
          End Sub
      End Class
  
      Public Class DataPoint
          Public Property Date As DateTime
          Public Property Politics As Double
          Public Property Entertainment As Double
          Public Property Travel As Double
  
          Public Shared Function GetPoints() As List(Of DataPoint)
              Return New List(Of DataPoint) From {
                  New DataPoint With { .Date = New DateTime(2016, 11, 1), .Politics = 65,  .Entertainment = 56, .Travel = 45 },
                  New DataPoint With { .Date = New DateTime(2016, 11, 2), .Politics = 78,  .Entertainment = 45, .Travel = 40 },
                  New DataPoint With { .Date = New DateTime(2016, 11, 3), .Politics = 95,  .Entertainment = 70, .Travel = 56 },
                  New DataPoint With { .Date = New DateTime(2016, 11, 4), .Politics = 110, .Entertainment = 82, .Travel = 47 },
                  New DataPoint With { .Date = New DateTime(2016, 11, 5), .Politics = 108, .Entertainment = 80, .Travel = 38 },
                  New DataPoint With { .Date = New DateTime(2016, 11, 6), .Politics = 52,  .Entertainment = 20, .Travel = 31 },
                  New DataPoint With { .Date = New DateTime(2016, 11, 7), .Politics = 46,  .Entertainment = 10, .Travel = 27 },
                  New DataPoint With { .Date = New DateTime(2016, 11, 8), .Politics = 70,  .Entertainment = Double.NaN, .Travel = 27 },
                  New DataPoint With { .Date = New DateTime(2016, 11, 9), .Politics = 86,  .Entertainment = Double.NaN, .Travel = 42 },
                  New DataPoint With { .Date = New DateTime(2016, 11, 10),.Politics = 92,  .Entertainment = 65, .Travel = Double.NaN },
                  New DataPoint With { .Date = New DateTime(2016, 11, 11),.Politics = 105, .Entertainment = 45, .Travel = 37 },
                  New DataPoint With { .Date = New DateTime(2016, 11, 12),.Politics = 115, .Entertainment = 56, .Travel = 21 },
                  New DataPoint With { .Date = New DateTime(2016, 11, 13),.Politics = 75,  .Entertainment = 10, .Travel = 10 },
                  New DataPoint With { .Date = New DateTime(2016, 11, 14),.Politics = 65,  .Entertainment = 0, .Travel = 5 }
              }
          End Function
      End Class
  End Namespace
  

You can use the SeriesPoint.IsEmpty property to check whether a point is empty.

Missing points are represented as empty points if the ScaleOptionsBase.ProcessMissingPoints property is set to InsertEmptyPoints.

Tip

• You can use scale breaks to hide specific data ranges from an axis.
• To limit data displayed in a chart, configure visual and whole axis ranges.
• If you use an argument axis with a date-time scale, you can exclude holidays, weekends or particular hours from a scale. Refer to Work Time and Workday Configuration for more information.

Show Isolated Points

The Chart does not draw a point between two empty points. To display a point in this case, enable the ShowIsolatedPoints property.

ShowIsolatedPoints = true	ShowIsolatedPoints = false

C#

LineSeriesView view = chart.Series[0].View as LineSeriesView;
view.ShowIsolatedPoints = true;

VB.NET

Dim view As LineSeriesView = TryCast(chart.Series(0).View, LineSeriesView)
view.ShowIsolatedPoints = True