Chartcontrol.Invalidate Visual different thread owns error

[habibalex]

ChartControl.InvalidateVisual() seems to update the charts faster than ForceRefresh, but I'm getting an error while using saying that a different thread owns it.

1. Is it possible to make ForceRefresh update faster?
2. What thread does ChartControl.InvalidateVisual() run on and how do I access it to do the proper update?

[NinjaTrader_Jesse]

Hello habibalex,

As noted in the help guide article for ForceRefresh, using Invalidate should not be used for this specific reason: http://ninjatrader.com/support/helpG...orce%2Brefresh

Instead, you would either need to "queue" a refresh with ForceRefresh, or complete an action that would force the chart to re-render like removing a drawing object. You can locate all the reasons a chart will forcibly refresh on the ForceRefresh help guide page.

One item that is fairly simple would be to add a dummy drawing object and then remove it right after adding it. For example:

Draw.Dot(this, "dummy", false, 0, Low[0], Brushes.Red);
RemoveDrawObject("dummy");

I look forward to being of further assistance.

[habibalex]

By using the dummy object, can I get updates faster than 250 ms?

[NinjaTrader_Jesse]

Hello habibalex,

Technically speaking yes, I tried putting this on a timer but this is certainly not a good way update the chart over and over quickly.

Not only would you be invoking rendering for the entire panel, you would be invoking DrawObject logic to both add and remove the object over and over. Considering the chart already renders at fixed intervals and for specific events, this would be a lot of CPU work to add for the little change. In my tests, I had used 30ms and had seen near 100% CPU use on a single chart, that would not be good for any situation.

Because this would take a heavy toll on the CPU it could cause problems, I would not recommend it for any type of force rendering in a loop or timer. Removing a draw object to refresh should be left to more targeted uses like clicking a button to update some data on the chart. I could see that this may be visually beneficial but this would not be an efficient way to invoke a faster render than the platform targets.

I look forward to being of further assistance.

[habibalex]

tbRender 00:00:00.4691424 force 00:00:00.3105562
forcing 36500:00:00.6130000
forcing 36500:00:00.2150000
tbRender 00:00:00.6864239 force 00:00:00.1689801
forcing 36500:00:00.5110000
forcing 36500:00:00.1410000
tbRender 00:00:00.8269360 force 00:00:00.3439161
forcing 36500:00:00.4340000
forcing 36500:00:00.1010000
forcing 36500:00:00.1020000
tbRender 00:00:00.5176778 force 00:00:00.2245939
tbRender 00:00:00.0115070 force 00:00:00.2361009
forcing 36500:00:00.1830000
forcing 36500:00:00.3250000
tbRender 00:00:00.4264496 force 00:00:00.1545505
tbRender 00:00:00.0025017 force 00:00:00.1570522
tbRender 00:00:00.3368318 force 00:00:00.4938840

Every line that says Forcing 365 has a the Draw.Dot on it.

the tbRender is the amount of time between OnRender calls
the force is the amount of time after Draw.Dot code has been called and OnRender is called. I don't think this is a good solution. Is there another way to get the OnRender to get called more consistently?

I can see that it takes as little as 2ms to update the chart. I only need the chart to update consistently within 150 - 200 ms. Ideally I would like it if the time between forcing an update and actually starting the OnRender call is within 50ms, which should be plenty of time.