Thread Safety in Utils.CalcColorBlend?

[Scanrate]

Hi,

I've been having some threading issues that seem to be related to TeeChart. I'm getting the following exception when my code is executed (by ASP.NET IIS) in several simultaneous requests:

Code: Select all

System.InvalidOperationException: Object is currently in use elsewhere. 
at System.Drawing.Graphics.FromImage(Image image) 
at Steema.TeeChart.Utils.CalcColorBlend(Color start, Color end, Int32 percentage) 
at Steema.TeeChart.Styles.Series.ModifySeriesColors(Color color) 
at Steema.TeeChart.Styles.CustomBar.ModifySeriesColors(Color color) 
at Steema.TeeChart.Styles.Series.Added() 
at Steema.TeeChart.Styles.SeriesCollection.Add(Series s) 
at Steema.TeeChart.Styles.Series..ctor(Chart c) 
at Steema.TeeChart.Styles.CustomBar..ctor(Chart c) 
at Steema.TeeChart.Styles.Bar..ctor(Chart c) 

My own code indicates, as expected from the stacktrace, that this happens when I call new Bar(ch); (ch being my Chart-object).

Using Reflector, it seems to stem from the fact that the Utils-class maintains a static Bitmap instance for calculating default gradient colors using FillRect and GetPixel. So when two Bars are constructed simultaneously, they both attempt to retrieve Graphics-handles for the same Bitmap. This seems odd and unnecessary. I would expect the calculation to be a simple linear progression which can be handled by multiplication, which should be much more efficient as well.

Is there some way I can avoid the (unnecessary) calculation, as I'm using solid colors for my bars? Or are there plans to fix this bug?

My TeeChart.dll is listed as v. 4.0.2010.13051.

[Yeray]

Hi Scanrate,

TeeChart is not thread-safe so you should control the accesses from different threads with semaphores or other threading techniques.

However, if you could arrange a simple example we could run as-is to reproduce the problem here, we will try to propose a workaround this issue and we'll investigate if we can skip the calculations you mention safety or not.