I want to add a broken line to my linechart. I am setting the YValue as double.NaN when there are no YValue to show.

It works fine except for the first point where it draws a vertical line as seen in the picture. How can I get rid of that one?

CodePudding user response：

There is no code in the question, but it would automatically work with double.NaN if you used the DataBindXY method on the Points property of the chart series, so I assume you are adding the DataPoints manually.

In this case, the IsEmpty property of the DataPoint must be set to true. So, if you create the DatePoints from the x/y values (for example, from two arrays with the actual values), you can set the IsEmpty property accordingly by checking the y value with:

 double.IsNaN(yValue)

A simple self-contained example might look something like this:

private readonly int[] _xArr = new int[] { 1, 2, 3, 4, 5 ,6, 7 };
private readonly double[] _yArr = new double[] { double.NaN, 0.9, 1.2, double.NaN, 1.3, 1.1, 1.4 };

private IEnumerable<DataPoint> DataPoints()
{
    return _xArr.Select((x, i) => new DataPoint(x, _yArr[i]) { IsEmpty = double.IsNaN(_yArr[i])});
}

For completeness, here a simple chart setup for a quick test:

private void Form1_Load(object sender, EventArgs e)
{
    var series = chart1.Series[0];

    series.LegendText = "Some Chart";
    series.ChartType = SeriesChartType.Line;
    series.IsValueShownAsLabel = true;
    foreach(var dp in DataPoints())
    {
        series.Points.Add(dp);
    }
}

The example would then look something like this with the data from above:

As one can see, this displays missing start points and interruptions as desired.