Hi All,


I add a data label (via an invisible point series) to a 3D bar chart in order to update a related data item each time a bar is displayed. Being a label, I seem to have no control over font, font size, text color, etc., and insufficient control over placement on the chart back wall when the chart scale changes. An example of this is the label starts in the top right corner of the chart back wall, and drops to the bottom right corner during the scale change. Is this a feature I wonder?

Here's the code:

// Invisible Point series...
NPointSeries pointSeries = new NPointSeries();

// Hide everything except the labels
pointSeries.UseXValues = true;
pointSeries.MarkerStyle.Visible = false;
pointSeries.DataLabelStyle.Format = "";
pointSeries.BorderStyle.Width = new NLength(0);
pointSeries.FillStyle.SetTransparencyPercent(100);
pointSeries.DataLabelStyle.TextStyle.TextOverlapsImage = true;
pointSeries.DataLabelStyle.TextStyle.BackplaneStyle.Visible = false;
pointSeries.DataLabelStyle.TextStyle.StringFormatStyle.HorzAlign = Nevron.HorzAlign.Right;
pointSeries.DataLabelStyle.TextStyle.StringFormatStyle.VertAlign = Nevron.VertAlign.Center;
pointSeries.DataLabelStyle.ArrowLength = new NLength(0);
pointSeries.FillStyle = new NColorFillStyle(Color.Transparent);

chart.Series.Add(pointSeries);


I've experimented using an NLabel, and placing this on the chart border. This works exactly once, since I can't add an updated title in the same location. The latest title gets added to the chart border in an unintended location.

Here's that code:

NLabel score;
string label = "";

label += safearray[1].ToString("0.000");

score = new NLabel(label);
score.FitAlignment = ContentAlignment.TopRight;
score.TextStyle.FontStyle = new NFontStyle("Arial", 10, FontStyle.Regular);
score.TextStyle.FillStyle = new NColorFillStyle(Color.Blue);
score.TextStyle.StringFormatStyle.HorzAlign = Nevron.HorzAlign.Left;

nChartControl1.Panels.Add(score);
score.Dock = DockStyle.Top;

score.Padding = new NMarginsL(5, 5, 5, 5);
nChartControl1.Refresh();

What's the best way to accomplish my goal? I want a clean (and prominent) label I can update each time a bar is printed, and I'd like the label text to overlap the bar (in the forefront).

Thanks and Regards,

Steve C.

Hi Steve,

Regarding your questions:

>> Being a label, I seem to have no control over font, font size, text color, etc., and insufficient control over placement on the chart back wall when the chart scale changes.

You can control the font of a data label through the series.DataLabelStyle.TextStyle.FontStyle property.
The color is controlled through the series.DataLabelStyle.TextStyle.FillStyle property.


>> An example of this is the label starts in the top right corner of the chart back wall, and drops to the bottom right corner during the scale change. Is this a feature I wonder?

Depends on the scale change. In general you can expect for a data label to change its location when the axis scales are changed, because a data label is attached to its data point and the data point's location is determined by the axes.


>> I've experimented using an NLabel, and placing this on the chart border. This works exactly once, since I can't add an updated title in the same location. The latest title gets added to the chart border in an unintended location.

You can update just the label's text instead of adding a new label instance every time. From this code it does not get clear what happens with the previously added label panels.

Best Regards,
Nevron Support Team

Thanks Nevron. I haven't gotten back to this yet, since the "point series with invisible data points" solution works 90% of the time. I'll get back to this soon with your recommendations to get the other 10%.

Steve C.