Internal NT ChartControl Inconsistencies

[aslane]

I realize this is deep in undocumented territory, but while doing some custom plots, I noticed some of the ChartControl vars do not stay consistent.

If I have a chart up with lastBar at right edge, all of the following vars look ok:

ChartControl.LastBarPainted <- index of last bar on chart (i.e. 7905)
ChartControl.FirstBarPainted <- index of first bar on chart (i.e. 7826)
ChartControl.BarsPainted <- number of bars painted (i.e. 80)

Now if I scroll the data to the left one bar by hitting the right arrow key, I get something like the following:

ChartControl.LastBarPainted <- 7906 This index does not exist yet!
ChartControl.FirstBarPainted <- 7827 This is good.
ChartControl.BarsPainted <- 80 Should be 79 now that a bar scrolled off.

The only var that seems to be correct is FirstBarPainted. This continues if you continue to scroll.

You can work around this, but I wanted to see if this is expected or a bug.

This is with B7.

[NinjaTrader_Dierk]

As you stated this is not supported. Thus there is no expected behavior.

[aslane]

Thanks, thats what I expected, but wanted to make sure.

That being the case, your example in code breaking changes doc of how to iterate thru bars is incorrect/misleading, as the LastBarPainted is not always accurate. You might want to take a look at that.

[NinjaTrader_Dierk]

Thanks for your feedback.

[bukkan]

I realize this is deep in undocumented territory, but while doing some custom plots, I noticed some of the ChartControl vars do not stay consistent.

If I have a chart up with lastBar at right edge, all of the following vars look ok:

ChartControl.LastBarPainted <- index of last bar on chart (i.e. 7905)
ChartControl.FirstBarPainted <- index of first bar on chart (i.e. 7826)
ChartControl.BarsPainted <- number of bars painted (i.e. 80)

Now if I scroll the data to the left one bar by hitting the right arrow key, I get something like the following:

ChartControl.LastBarPainted <- 7906 This index does not exist yet!
ChartControl.FirstBarPainted <- 7827 This is good.
ChartControl.BarsPainted <- 80 Should be 79 now that a bar scrolled off.

The only var that seems to be correct is FirstBarPainted. This continues if you continue to scroll.

You can work around this, but I wanted to see if this is expected or a bug.

This is with B7.

dont think that is wrong. you got to do is

int lastbar = Math.Min(Bars.Count - 1, ChartControl.LastBarPainted);
int barspainted = lastbar - ChartControl.FirstBarPainted;

[NinjaTrader_Dierk]

Thanks, thats what I expected, but wanted to make sure.

That being the case, your example in code breaking changes doc of how to iterate thru bars is incorrect/misleading, as the LastBarPainted is not always accurate. You might want to take a look at that.

Please closely review the code breaking section of the upgrade document you should have received to understand that there is no reference to LastBarPainted.