Real-time in WPF

[Jay]

I noticed that the WPF "chart" class does not have the RealTime methods from the WinForms API.

 i.e.

chart1.RealTime.BeginAddData(1,

RealTimeAction.Append);chart1.Data[0, 0] = dPotential;

chart1.RealTime.EndAddData(radioButton4.Checked,

true);

 Is there another way to try out real-time data in the WPF beta?

[JuanC]

We do not support our realtime API yet in WPF but we do support ObservableCollection<T> so if you add objects to the collection pointed to by the ItemsSource property, we will update the chart.

Regards,

JuanC

[binford]

Is your realtime API still not available in WPF? If not, is it on your roadmap?

[JuanC]

We do not have a realtime API yet in WPF.

Can you describe more about your scenario, e.g. how often do you plan to provide new data, do you need a "circular buffer" storing only the last N points, etc.

JuanC

[binford]

Our measurement data is aquired with 200hz, but the widget obviously does not have to refresh that fast because no human is able to keep up with this information rate. An refresh rate of 5hz should be sufficient. We do not care about the implementation details, but a circular buffer is surely what I would chose if I had to code the widget myself.

Another requirement is that one should be able too zoom into a fixed area, say from 00:00:01 to 00:00:02. Note that the chart in zoom mode is static, which means that there are no new points added to the zoomed part. Zooming should not require the data feed to stop. After the zooming operation is done, the previously displayed data + any new data should be visible ("zoom-out").

I know that those requirements are quite challenging but If you could provide this feature it will surely set you ahead of your (many) competitors. I've evaluated 30+ charting SDKs by now, and from our 4 top candidates only one looks like he provides this feature or at least some API methods to do it ourselves QUICKLY. This is National Instruments Measurement Studio.

Regards,

Janosch

[JuanC]

How many points do you need the chart to keep? We are researching on a possible implementation for this feature and would like to know about your real world use.

You mentioned NI which I think is a WinForms/ActiveX control (not WPF), I just tested our WinForms control and we can definitely work with a 5hz refresh rate. Our winforms control does not have a feature where zooming would freeze the chart so you would probably have to track when the chart is in zoom mode and not pass new data.

Thanks for the detailed information you have provided, we will post here as soon as we have a build supporting this functionality.

JuanC

[JuanC]

We have added realtime support to our development branch. The API is the same as our WinForms control and we have added some functionality including the ability to ignore new points while zoomed.

We are not sure when this will be merged into the release branch but we can provide access to these bits which will give you chance to test it and provide feedback.

Regards,

JuanC