Develop Reference

How to create Box Plot for a series of data without x values

I am having difficulty creating a box plot for a set of row objects contained in a list. The data itself is populating fine enough but the chart creates a different x value for each object in the list, which is not intended. Perhaps I am using the wrong binding method on the list? Here is the snippet of code in which the binding occurs:
foreach (DataRow row in myDataSet.Tables[0].Rows)
{
colValues.Add(row["Freight Cost/ Pc - $"]);
}
chart1.Series["Series1"].Points.DataBindY(colValues);
edit:
It is a list. It contains each row value of column "Freight Cost/ Pc -$". I believe I only have one series. It is currently creating an x value for each y value in the list. I want only one independent value for every y value. In other words, I am dealing with a univariate sample. I don't even get why this is an issue. I was under the impression that a box plot was strictly used to display descriptive statistics related to univariate data.

A DataPoint of ChartType BoxPlot is a graphical depiction of statistical data.
You have two basic ways to use a BoxPlot chart:
You can add multiple DataPoints e.g. by using the AddXY call. For this you will have to provide (at least) six Y-Values containing the statistical values to show.
Or you can 'bind' a DataPoint to another Series in the Chart. If you have multiple Series you can show their stats in one BoxPlot DataPoint each.
The main difference is that in the first case you need to already have the stats while the second way will let the chart do the calculations on the series of DataPoints. The way to make that work is not by normal data binding but by using the BoxPlotSeries custom property:
Series BS = chart1.Series.Add("BoxPlotSeries");
BS.ChartType = SeriesChartType.BoxPlot;
BS.Points.Add(new DataPoint(55, 0));
BS.Points[0]["BoxPlotSeries"] = "S1";
After creating a random series S1 with 50 DataPoints, I create a BoxPlot series, add one point at x=55 and relate the point's Custom property BoxPlotSeries
Here is a result:
By regular binding the Points to your List you have effectively chosen method one and see many BoxPlot points. Instead style the Series to your liking as chartType Point, Line, Column or what you want; then add a second Series with one DataPoint, relating it to the data series, like in my code example..
I have chosen my X-Value so that the BoxPlot point sits to the right of the data. If your data do not have meaningful i.e. numeric X-Values they are displayed in order and you can place the BoxPlot point at S1.Points.Count or Count + 1 or +2..
Note that if you have a lot of DataPoints the BoxPlotPoint will look so thin you can hardly see it at all.
In that case it would be nice if you could simply make it wider.
There is a set of Custom Properties, namely
PointWidth and PixelPointWidth, MinPixelPointWidth and MaxPixelPointWidth.
BS["MinPixelPointWidth"] = "15";
BS["MaxPixelPointWidth"] = "25";
But you may prefer to keep the BoxPlot points separate by adding a second ChartArea where you place the BoxPlot series:
Here are the positioning and styling calls used for the above screenshot:
ChartArea A1 = chart1.ChartAreas[0];
Series S1 = chart1.Series[0];
A1.AxisX.Interval = 50;
ChartArea A2 = chart1.ChartAreas.Add("A2");
A2.AlignWithChartArea = "A1";
A2.AlignmentOrientation = AreaAlignmentOrientations.Horizontal;
A2.AlignmentStyle = AreaAlignmentStyles.PlotPosition;
A1.Position.Width *= 0.85f;
A2.Position.Y = A1.Position.Y;
A2.Position.X = A1.Position.Right;
A2.Position.Width = A1.Position.Width * 0.15f;
A2.AxisX.LabelStyle.ForeColor = Color.Transparent;
A2.AxisX.MajorGrid.Enabled = false;
A2.AxisX.MajorTickMark.Enabled = false;
A2.AxisX.Minimum = 0;
A2.AxisX.Maximum = 2;
A2.AxisY.Interval = 10;
A2.AxisY.Maximum = A1.AxisY.Maximum;
A2.AxisY.Minimum = A1.AxisY.Minimum;
Series BS = chart1.Series.Add("BoxPlotSeries");
BS.ChartArea = "A2";
BS.ChartType = SeriesChartType.BoxPlot;
BS.Points.Add(new DataPoint(1, 0));
DataPoint DPT = BS.Points[BS.Points.Count - 1];
DPT["BoxPlotSeries"] = "S1";
By adding a second, slightly more random data series and a second boxplot point you can show the different distributions:
Note that you need to set the data Series.Colors explictly to allow referencing them for the BoxPlot points..:
S1.Color = Color.SteelBlue;
S2.Color = Color.DarkKhaki;
...
DPT1.Color = chart1.Series["S1"].Color;
DPT2.Color = chart1.Series["S2"].Color;

C# WinForms Charts configuration

I am trying to plot a file's byte count over a C# WinForms bar graph. As such, the X-axis will have values 0-255 (if greater than zero) and the Y-axis varies upon the length of the file and the byte distribution. The code is as follows:
for (int i = 0; i < byteDistribution.Count; i++)
{
if (byteDistribution[i] > 0)
{
Series series = new Series(i.ToString());
series.Points.AddXY(i, byteDistribution[i]);
// PointWidth has no affect?
series.SetCustomProperty("PointWidth", "1");
this.crtBytes.Series.Add(series);
}
Questions:
This works well but the way the chart is shown is not to my liking.
I would like each bar to fill in as much space as possible (ie. no
margin / border). From what I've read elsewhere it was suggested to
use PointWidth or PixelPointWidth but none of these approaches is
working.
Is there a way to remove the inner black grid lines from
showing? Ideally, I would like the bottom X-axis numbering to remain just the same, but remove the grid lines.

For removing the gaps:
series["PointWidth"] = "1";
For removing the gridlines:
chartArea.AxisX.MajorGrid = new FChart.Grid {Enabled = false};
chartArea.AxisY.MajorGrid = new FChart.Grid { Enabled = false };
UPDATE:
I think your problem is that you create a new series for each data point. So you also get the "color effect". Just create ONE series, add it to the chart area and add all data points to this series.
Series series = new Series();
this.crtBytes.Series.Add(series);
series.SetCustomProperty("PointWidth", "1");
for (int i = 0; i < byteDistribution.Count; i++)
{
if (byteDistribution[i] > 0)
{
series.Points.AddXY(i, byteDistribution[i]);
// PointWidth has no affect?
}
}

PointWidth property is a relative amount, try something like series["PointWidth"] = 1.25.
The black lines are called MajorGrid, use chartArea.MajorGrid.Enabled = False.

Chart - Automatic highlighting Zero Points

So basically I have a graph as below in the image, I am going to be implementing some check boxes to enable and disable each line graph.
My main question is:
As you can see on the graphs there is dips in the data down to ZERO - How do I get these to automatically highlight for the user to see!
I.e. Set a point on the X Axis that displays interval!

One way would be to add a another Series of ChartType Point and add only those Zero Points as red dots..:
// add a new Series:
Series sz = chart1.Series.Add("Zeroes");
sz.ChartType = SeriesChartType.Point;
sz.Color = Color.Red;
sz.BorderWidth = 3;
// add Points wherever the other series is zero or less
foreach (DataPoint dp in chart1.Series[0].Points )
{
if (dp.YValues[0] <= 0) sz.Points.AddXY(dp.XValue, 0);
}
If you need to check on more Series you can repeat the loop for them..

How to add spikes to line on Winform chart?

I am drawing a line on a graph from numbers read from a text file. There is a number on each line of the file which corresponds to the X co-ordinate while the Y co-ordinate is the line it is on.
The requirements have now changed to include "special events" where if the number on the line is followed by the word special a spike will appear like image below:
Currently the only way I can find is to use a line for each spike, however there could be a large of these special events and so needs to be modular. This seems an efficient and bad way to program it.
Is it possible to add the spikes to the same graph line? Or is it possible to use just one additional line and have it broken (invisible) and only show where the spikes are meant to be seen?
I have looked at using bar graphs but due to other items on the graph I cannot.

The DataPoints of a Line Chart are connected so it is not possble to really break it apart. However each segment leading to a DataPoint can have its own color and that includes Color.Transparent which lends itself to a simple trick..
Without adding extra Series or Annotations, your two questions can be solved like this:
To simply add the 'spikes' you show us in the 2nd graph, all you need to do is to insert 2 suitable datapoints, the 2nd being identical to the point the spike is connected to.
To add an unconnected line you need to 'jump' to its beginning by adding one extra point with a transparent color.
Here are two example methods:
void addSpike(Series s, int index, double spikeWidth)
{
DataPoint dp = s.Points[index];
DataPoint dp1 = new DataPoint(dp.XValue + spikeWidth, dp.YValues[0]);
s.Points.Insert(index+1, dp1);
s.Points.Insert(index+2, dp);
}
void addLine(Series s, int index, double spikeDist, double spikeWidth)
{
DataPoint dp = s.Points[index];
DataPoint dp1 = new DataPoint(dp.XValue + spikeDist, dp.YValues[0]);
DataPoint dp2 = new DataPoint(dp.XValue + spikeWidth, dp.YValues[0]);
DataPoint dp0 = dp.Clone();
dp1.Color = Color.Transparent;
dp2.Color = dp.Color;
dp2.BorderWidth = 2; // optional
dp0.Color = Color.Transparent;
s.Points.Insert(index + 1, dp1);
s.Points.Insert(index + 2, dp2);
s.Points.Insert(index + 3, dp0);
}
You can call them like this:
addSpike(chart1.Series[0], 3, 50d);
addLine(chart1.Series[0], 6, 30d, 80d);
Note that they add 2 or 3 DataPoints to the Points collection!
Of course you can set the Color and width (aka BorderWidth) of the extra lines as you wish and also include them in the params list..
If you want to keep the points collection unchanged you also can simply create one 'spikes series' and add the spike points there. The trick is to 'jump' to the new points with a transparent line!

VS2010 Chart control, how to display a blank chart?

I'm trying to use the chart control on a windows form and have it working, plotting some real time data, however before the data arrives nothing is displayed. I would like to show an empty graph with an X Y of 10 30 but still have the graph auto range if values go above this.
I cannot find a property to show the "blank" graph it this possible and if so how?
thanks

You can hide all data of a Series by making its line color Transparent. If you also set its LegendText to be " " all you can see are the Axis ticks. you can control them by adding a few Points and by setting the Minimum and Maximum values:
// short reference for our dummy:
Series S0 = chart1.Series[0];
// a simple type
S0.ChartType = SeriesChartType.Line;
// set 10 point with x-values going from 0-100 and y-values going from 1-10:
for (int i = 0; i < 100; i +=10) S0.Points.AddXY(i , i / 10);
// or add only a few, e.g. the first and last points:
//S0.Points.AddXY(100, 10);
//S0.Points.AddXY(0, 10);
// hide the line:
S0.Color = Color.Transparent;
// hide the legend text (it will still take up a little space, though)
S0.LegendText = " ";
// limit the axis to the target values
chart1.ChartAreas[0].AxisX.Maximum = 100;
chart1.ChartAreas[0].AxisX.Minimum = 0;
The result looks like an empty chart: