How do I display a nice line graph without breakages in the line when a graph has hidden points with values of DBNull?

[User (Legacy)]

Hi,

I have a series that is displayed as a line graph in a ChartFX for VS .NET 

2005 chart.  It uses data from a column that has some DBNull values.

The line prints out, with the DBNull points printing as hidden points. 

These hidden points cause breaks in the nice line.

I would like the line graph to appear unbroken.  I would like a straight 

line to be drawn from the closest point on its left to the closest point on 

its right.  How can I accomplish this?

(Note: I would definitely rather not have to loop through all values and 

assign fake values to the points that would make the line graph work out to 

have no line breaks.  I realize that I could calculate a weighted average 

value between the closest point on the left and right, and set the hidden 

point's value to this fake value.)

Thanks a lot for your help,

Brook Hunter

[Software FX]

You will need a separate set of dates for each series, your data needs to 

look like this:

Date1        Series1        Date2        Series2

1/1/2001    30            1/1/2001          40

1/3/2001    20            1/4/2001          45

1/6/2001    50            1/5/2001          70

null            null            1/6/2001          60

Notice that using this approach, all null values (if any) end up at the end 

of the dataset.

-- 

Francisco Padron

www.chartfx.com

[wlo413]

I have got a similar issue with this.

Working with C#, I am plotting a real time data stream against time where my data arrives at unknown time intervals. My chart is updated once a second, via a timer event that refreshes the chart. Since the data coming is potentially never ending, I dont want to plot every single data sample that has arrived, otherwise, I might end up with a chart that contains an infinate number of data. So I created a scrolling window, where I only plot the last minute or so of data.

I need to use a line graph where I pass the chart data as an (x,y) coordinate set, as described in the scatter plot documentation. However, I want my data points to be connected with a line, hence my need to plot this as a line graph.

Since my data arrives at irregular intervals, my plot ends up looking like this:

chart1.Data.Y[1, 0] = 20;

chart1.Data.Y[1, 1] = null;  // no data sample at this time

chart1.Data.Y[1, 2] = 25;

chart1.Data.Y[1, 3] = null; // no data sample at this time

chart1.Data.Y[1, 4] = null; // no data sample at this time

chart1.Data.Y[1, 5] = 22;

chart1.Data.Y[1, 6] = 23;

chart1.Data.Y[1, 7] = null; // no data sample at this time

....

....

....

....

The line breaks where the data point is null, but I want a continuous line between two available points. I think, essentually, I want a scatter plot that is connected with a line.

 Is there anyway I can acheive this given the nature of my data?

[CarlosAC]

Hi Brook and wlo413.  Unfortunately, you will need to set the

calculated value (average) to the hidden point.  If you set hidden to the

point, the line will be broken.