TaskLinkOptions.ArrowHeight Property

using System;
using System.Windows.Forms;
using DevExpress.XtraCharts;
// ... 

private void Form1_Load(object sender, EventArgs e) {
    // Create a new chart. 
    ChartControl overlappedGanttChart = new ChartControl();

    // Create two Gantt series. 
    Series series1 = new Series("Planned", ViewType.Gantt);
    Series series2 = new Series("Completed", ViewType.Gantt);

    // Set the date-time values scale type for both series, 
    // as it is qualitative, by default. 
    series1.ValueScaleType = ScaleType.DateTime;
    series2.ValueScaleType = ScaleType.DateTime;

    // Add points to them. 
    series1.Points.Add(new SeriesPoint("Market analysis", new DateTime[] { 
    new DateTime(2006, 8, 16), new DateTime(2006, 8, 23) }));
    series1.Points.Add(new SeriesPoint("Feature planning", new DateTime[] { 
    new DateTime(2006, 8, 23), new DateTime(2006, 8, 26) }));
    series1.Points.Add(new SeriesPoint("Implementation", new DateTime[] { 
    new DateTime(2006, 8, 26), new DateTime(2006, 9, 26) }));
    series1.Points.Add(new SeriesPoint("Testing & bug fixing", new DateTime[] { 
    new DateTime(2006, 9, 26), new DateTime(2006, 10, 10) }));

    series2.Points.Add(new SeriesPoint("Market analysis", new DateTime[] { 
    new DateTime(2006, 8, 16), new DateTime(2006, 8, 23) }));
    series2.Points.Add(new SeriesPoint("Feature planning", new DateTime[] { 
    new DateTime(2006, 8, 23), new DateTime(2006, 8, 26) }));
    series2.Points.Add(new SeriesPoint("Implementation", new DateTime[] { 
    new DateTime(2006, 8, 26), new DateTime(2006, 9, 10) }));

    // Add both series to the chart. 
    overlappedGanttChart.Series.AddRange(new Series[] { series1, series2 });

    // Access the view-type-specific options of the series. 
    ((GanttSeriesView)series1.View).BarWidth = 0.6;
    ((GanttSeriesView)series2.View).BarWidth = 0.3;

    // Access the type-specific options of the diagram. 
    GanttDiagram myDiagram = (GanttDiagram)overlappedGanttChart.Diagram;

    myDiagram.AxisY.Interlaced = true;
    myDiagram.AxisY.GridSpacing = 10;
    myDiagram.AxisY.Label.Angle = -30;
    myDiagram.AxisY.DateTimeOptions.Format = DateTimeFormat.MonthAndDay;

    // Add task links for the first Gantt series. 
    ((GanttSeriesView)series1.View).LinkOptions.ArrowHeight = 7;
    ((GanttSeriesView)series1.View).LinkOptions.ArrowWidth = 11;
    for (int i = 1; i < series1.Points.Count; i++) {
        series1.Points[i].Relations.Add(series1.Points[i - 1]);
    }

    // Add a progress line. 
    ConstantLine progress =
    new ConstantLine("Current progress", new DateTime(2006, 9, 10));
    progress.ShowInLegend = false;
    progress.Title.Alignment = ConstantLineTitleAlignment.Far;
    myDiagram.AxisY.ConstantLines.Add(progress);

    // Adjust the legend. 
    overlappedGanttChart.Legend.AlignmentHorizontal = 
        LegendAlignmentHorizontal.Right;

    // Add a title to the chart (if necessary). 
    overlappedGanttChart.Titles.Add(new ChartTitle());
    overlappedGanttChart.Titles[0].Text = "R&am