Key Hints for Chart for WPF

The following top tips for Chart for WPF and Silverlight will help you when you use the C1Chart control.

Tip 1: Use the BeginUpdate()/EndUpdate() methods to improve performance

This improves performance since the redrawing occurs only once after a call of the EndUpdate() method.

For example:

Visual Basic	Copy Code
' start update C1Chart1.BeginUpdate() Dim nser As Integer = 10, npts As Integer = 100 For iser As Integer = 1 To nser ' create data arrays Dim x(npts - 1) As Double, y(npts - 1) As Double For ipt As Integer = 0 To npts - 1 x(ipt) = ipt y(ipt) = (1 + 0.05 * iser) * Math.Sin(0.1 * ipt + 0.1 * iser) Next ' create data series and add it to the chart Dim ds = New XYDataSeries() ds.XValuesSource = x ds.ValuesSource = y C1Chart1.Data.Children.Add(ds) Next ' set chart type C1Chart1.ChartType = ChartType.Line ' finish update C1Chart1.EndUpdate()

Visual Basic

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' start update
  C1Chart1.BeginUpdate()

  Dim nser As Integer = 10, npts As Integer = 100
  For iser As Integer = 1 To nser
    ' create data arrays
    Dim x(npts - 1) As Double, y(npts - 1) As Double
    For ipt As Integer = 0 To npts - 1
      x(ipt) = ipt
      y(ipt) = (1 + 0.05 * iser) * Math.Sin(0.1 * ipt + 0.1 * iser)
    Next
    ' create data series and add it to the chart
    Dim ds = New XYDataSeries()
    ds.XValuesSource = x
    ds.ValuesSource = y
    C1Chart1.Data.Children.Add(ds)
  Next

  ' set chart type
  C1Chart1.ChartType = ChartType.Line

  ' finish update
  C1Chart1.EndUpdate()

C#	Copy Code
// start update c1Chart1.BeginUpdate(); int nser = 10, npts = 100; for (int iser = 0; iser < nser; iser++) { // create data arrays double[] x = new double[npts], y = new double[npts]; for (int ipt = 0; ipt < npts; ipt++) { x[ipt] = ipt; y[ipt] = (1 + 0.05 * iser) * Math.Sin(0.1 * ipt + 0.1 * iser); } // create data series and add it to the chart XYDataSeries ds = new XYDataSeries(); ds.XValuesSource = x; ds.ValuesSource = y; c1Chart1.Data.Children.Add(ds); } // set chart type c1Chart1.ChartType = ChartType.Line; // finish update c1Chart1.EndUpdate();

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// start update
  c1Chart1.BeginUpdate();

  int nser = 10, npts = 100;
  for (int iser = 0; iser < nser; iser++)
  {
    // create data arrays
    double[] x = new double[npts], y = new double[npts];
    for (int ipt = 0; ipt < npts; ipt++)
    {
      x[ipt] = ipt;
      y[ipt] = (1 + 0.05 * iser) * Math.Sin(0.1 * ipt + 0.1 * iser);
    }

    // create data series and add it to the chart
    XYDataSeries ds = new XYDataSeries();
    ds.XValuesSource = x; ds.ValuesSource = y;
    c1Chart1.Data.Children.Add(ds);
  }

  // set chart type
  c1Chart1.ChartType = ChartType.Line;

  // finish update
  c1Chart1.EndUpdate();

Tip 2: Use the Line or Area type chart for large data arrays

The line and area charts provide the best performance when you have a lots of data values.

To get better performance, enable built-in optimization for large data by setting the attached property, LineAreaOptions.OptimizationRadius. For example:

Visual Basic	Copy Code
LineAreaOptions.SetOptimizationRadius(C1Chart1, 1.0)

C#	Copy Code
LineAreaOptions.SetOptimizationRadius(c1Chart1, 1.0);

It's recommended you use small values 1.0 - 2.0 as radius. A larger value may affect the accuracy of the plot.

Tip 3: Update the appearance and behavior of a plot element using the DataSeries.PlotElementLoaded event

When any plot element (bar,column,pie, etc) is loaded it fires the PlotElementLoaded event. During this event you have access to the plot element properties as well as to the corresponding data point.

The following code sets the colors of points depending on its y-value. For example:

Visual Basic	Copy Code
' create data arrays Dim npts As Integer = 100 Dim x(npts - 1) As Double, y(npts - 1) As Double For ipt As Integer = 0 To npts - 1 x(ipt) = ipt y(ipt) = Math.Sin(0.1 * ipt) Next ' create data series Dim ds = New XYDataSeries() ds.XValuesSource = x ds.ValuesSource = y ' set event handler AddHandler ds.PlotElementLoaded, AddressOf PlotElement_Loaded ' add data series to the chart C1Chart1.Data.Children.Add(ds) ' set chart type C1Chart1.ChartType = ChartType.LineSymbols ... ' event handler Sub PlotElement_Loaded(ByVal sender As Object, ByVal args As EventArgs) Dim pe = CType(sender, PlotElement) If Not TypeOf pe Is Lines Then Dim dp As DataPoint = pe.DataPoint ' normalized y-value(from 0 to 1) Dim nval As Double = 0.5 * (dp.Value + 1) ' fill from blue(-1) to red(+1) pe.Fill = New SolidColorBrush(Color.FromRgb(CByte(255 * nval), _ 0, CByte(255 * (1 - nval)))) End If End Sub

Visual Basic

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' create data arrays
  Dim npts As Integer = 100
  Dim x(npts - 1) As Double, y(npts - 1) As Double
  For ipt As Integer = 0 To npts - 1
    x(ipt) = ipt
    y(ipt) = Math.Sin(0.1 * ipt)
  Next

  ' create data series
  Dim ds = New XYDataSeries()
  ds.XValuesSource = x
  ds.ValuesSource = y

  ' set event handler
  AddHandler ds.PlotElementLoaded, AddressOf PlotElement_Loaded

  ' add data series to the chart
  C1Chart1.Data.Children.Add(ds)

  ' set chart type
  C1Chart1.ChartType = ChartType.LineSymbols

...

  ' event handler
  Sub PlotElement_Loaded(ByVal sender As Object, ByVal args As EventArgs)
    Dim pe = CType(sender, PlotElement)
    If Not TypeOf pe Is Lines Then
      Dim dp As DataPoint = pe.DataPoint
      ' normalized y-value(from 0 to 1)
      Dim nval As Double = 0.5 * (dp.Value + 1)
      ' fill from blue(-1) to red(+1)
      pe.Fill = New SolidColorBrush(Color.FromRgb(CByte(255 * nval), _
       0, CByte(255 * (1 - nval))))
    End If
  End Sub

C#	Copy Code
// create data arrays int npts = 100; double[] x = new double[npts], y = new double[npts]; for (int ipt = 0; ipt < npts; ipt++) { x[ipt] = ipt; y[ipt] = Math.Sin(0.1 * ipt); } // create data series XYDataSeries ds = new XYDataSeries(); ds.XValuesSource = x; ds.ValuesSource = y; // set event handler ds.PlotElementLoaded += (s, e) => { PlotElement pe = (PlotElement)s; if (!(pe is Lines)) // skip lines { DataPoint dp = pe.DataPoint; // normalized y-value(from 0 to 1) double nval = 0.5(dp.Value + 1); // fill from blue(-1) to red(+1) pe.Fill = new SolidColorBrush( Color.FromRgb((byte)(255 nval), 0, (byte)(255 * (1-nval)))); } }; // add data series to the chart c1Chart1.Data.Children.Add(ds); // set chart type c1Chart1.ChartType = ChartType.LineSymbols;

Copy Code

// create data arrays
  int npts = 100;
  double[] x = new double[npts], y = new double[npts];
  for (int ipt = 0; ipt < npts; ipt++)
  {
    x[ipt] = ipt;
    y[ipt] = Math.Sin(0.1 * ipt);
  }

  // create data series
  XYDataSeries ds = new XYDataSeries();
  ds.XValuesSource = x; ds.ValuesSource = y;

  // set event handler
  ds.PlotElementLoaded += (s, e) =>
    {
      PlotElement pe = (PlotElement)s;
      if (!(pe is Lines)) // skip lines
      {
        DataPoint dp = pe.DataPoint;
      
        // normalized y-value(from 0 to 1)
        double nval = 0.5*(dp.Value + 1);

        // fill from blue(-1) to red(+1)
        pe.Fill = new SolidColorBrush(
          Color.FromRgb((byte)(255 * nval), 0, (byte)(255 * (1-nval))));
      }
    };

  // add data series to the chart
  c1Chart1.Data.Children.Add(ds);

  // set chart type
  c1Chart1.ChartType = ChartType.LineSymbols;

Tip 4: Data point labels and tooltips

To create a data point label or tooltip, you should set the data template for the PointLabelTemplate or PointTooltipTemplate property.

The following sample code shows the index for each data point.

XAML	Copy Code
<c1chart:C1Chart Name="c1Chart1" ChartType="XYPlot"> <c1chart:C1Chart.Data> <c1chart:ChartData> <!-- source collection --> <c1chart:ChartData.ItemsSource> <PointCollection> <Point X="1" Y="1" /> <Point X="2" Y="2" /> <Point X="3" Y="3" /> <Point X="4" Y="2" /> <Point X="5" Y="1" /> </PointCollection> </c1chart:ChartData.ItemsSource> <c1chart:XYDataSeries SymbolSize="16,16" XValueBinding="{Binding X}" ValueBinding="{Binding Y}"> <c1chart:XYDataSeries.PointLabelTemplate> <DataTemplate> <!-- display point index at the center of point symbol --> <TextBlock c1chart:PlotElement.LabelAlignment="MiddleCenter" Text="{Binding PointIndex}" /> </DataTemplate> </c1chart:XYDataSeries.PointLabelTemplate> </c1chart:XYDataSeries> </c1chart:ChartData> </c1chart:C1Chart.Data> </c1chart:C1Chart>

XAML

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<c1chart:C1Chart Name="c1Chart1" ChartType="XYPlot">
  <c1chart:C1Chart.Data>
    <c1chart:ChartData>
      <!-- source collection -->
      <c1chart:ChartData.ItemsSource>
        <PointCollection>
          <Point X="1" Y="1" />
          <Point X="2" Y="2" />
          <Point X="3" Y="3" />
          <Point X="4" Y="2" />
          <Point X="5" Y="1" />
        </PointCollection>
      </c1chart:ChartData.ItemsSource>

      <c1chart:XYDataSeries SymbolSize="16,16"
        XValueBinding="{Binding X}" ValueBinding="{Binding Y}">
        <c1chart:XYDataSeries.PointLabelTemplate>
          <DataTemplate>
            <!-- display point index at the center of point symbol  -->
            <TextBlock c1chart:PlotElement.LabelAlignment="MiddleCenter"
                       Text="{Binding PointIndex}" />
          </DataTemplate>
        </c1chart:XYDataSeries.PointLabelTemplate>
      </c1chart:XYDataSeries>
    </c1chart:ChartData>
  </c1chart:C1Chart.Data>
</c1chart:C1Chart>

Tip 5: Save chart as image

The following method saves chart image as png-file.

Visual Basic	Copy Code
Sub Using stm = System.IO.File.Create(fileName) c1Chart1.SaveImage(stm, ImageFormat.Png) End Using

C#	Copy Code
using (var stm = System.IO.File.Create(fileName)) { c1Chart1.SaveImage(stm, ImageFormat.Png); }

Tip 6: Printing chart

The following code prints the specified chart on the default printer with the default settings. For example:

Visual Basic	Copy Code
Dim pd = New PrintDialog() pd.PrintVisual(C1Chart1, "chart")

C#	Copy Code
new PrintDialog().PrintVisual(c1Chart1, "chart");

Tip 7: Mixing Cartesian chart types

You can easily mix different chart types on the same Cartesian plot using the ChartType property.

The following code creates three data series: the first is area, the second is step, and the third has the default chart type (line).

Visual Basic	Copy Code
Dim nser As Integer = 3, npts As Integer = 25 For iser As Integer = 1 To nser ' create data arrays Dim x(npts - 1) As Double, y(npts - 1) As Double For ipt As Integer = 0 To npts - 1 x(ipt) = ipt y(ipt) = (1 + 0.05 * iser) * Math.Sin(0.1 * ipt + 0.1 * iser) Next ' create data series and add it to the chart Dim ds = New XYDataSeries() ds.XValuesSource = x ds.ValuesSource = y C1Chart1.Data.Children.Add(ds) Next 'default chart type C1Chart1.ChartType = ChartType.Line ' 1st series C1Chart1.Data.Children(0).ChartType = ChartType.Area ' 2nd series C1Chart1.Data.Children(1).ChartType = ChartType.Step

Visual Basic

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Dim nser As Integer = 3, npts As Integer = 25
  For iser As Integer = 1 To nser
    ' create data arrays
    Dim x(npts - 1) As Double, y(npts - 1) As Double
    For ipt As Integer = 0 To npts - 1
      x(ipt) = ipt
      y(ipt) = (1 + 0.05 * iser) * Math.Sin(0.1 * ipt + 0.1 * iser)
    Next
    ' create data series and add it to the chart
    Dim ds = New XYDataSeries()
    ds.XValuesSource = x
    ds.ValuesSource = y
    C1Chart1.Data.Children.Add(ds)
  Next

  'default chart type
  C1Chart1.ChartType = ChartType.Line

  ' 1st series
  C1Chart1.Data.Children(0).ChartType = ChartType.Area

  ' 2nd series
  C1Chart1.Data.Children(1).ChartType = ChartType.Step

C#	Copy Code
int nser = 3, npts = 25; for (int iser = 0; iser < nser; iser++) { // create data arrays double[] x = new double[npts], y = new double[npts]; for (int ipt = 0; ipt < npts; ipt++) { x[ipt] = ipt; y[ipt] = (1 + 0.05 * iser) * Math.Sin(0.1 * ipt + 0.1 * iser); } // create data series and add it to the chart XYDataSeries ds = new XYDataSeries(); ds.XValuesSource = x; ds.ValuesSource = y; c1Chart1.Data.Children.Add(ds); } //default chart type c1Chart1.ChartType = ChartType.Line; // 1st series c1Chart1.Data.Children[0].ChartType = ChartType.Area; // 2nd series c1Chart1.Data.Children[1].ChartType = ChartType.Step;

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int nser = 3, npts = 25;
  for (int iser = 0; iser < nser; iser++)
  {
    // create data arrays
    double[] x = new double[npts], y = new double[npts];
    for (int ipt = 0; ipt < npts; ipt++)
    {
      x[ipt] = ipt;
      y[ipt] = (1 + 0.05 * iser) * Math.Sin(0.1 * ipt + 0.1 * iser);
    }

    // create data series and add it to the chart
    XYDataSeries ds = new XYDataSeries();
    ds.XValuesSource = x; ds.ValuesSource = y;
    c1Chart1.Data.Children.Add(ds);
  }

  //default chart type
  c1Chart1.ChartType = ChartType.Line;

  // 1st series
  c1Chart1.Data.Children[0].ChartType = ChartType.Area;

  // 2nd series
  c1Chart1.Data.Children[1].ChartType = ChartType.Step;