[solved] How to hide/show series in a TChartListBox?
lazarus / 55-TAChart

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Muso · 2022-02-21 19:02

I have a chart with many series. The user should can hide/show them in
the chart, but he should also be able to filter series to select them
for certain purposes.

Therefore I have a TChartListBox in a dialog. When the user presses in
the dialog a button, then for example only series with the name
"Start_XXX" should be shown in the TChartListBox. This visibility
change should only happen in the TChartListBox, not in the chart.

Is this possible and if so, how?

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wp · 2022-02-21 20:52

The chartlistbox is re-populated at a variety of occasions. Whenever
this happens events OnAddSeries are fired before a series is added to
the listbox. These events have a boolean parameter Skip which you can
set to true if you want to avoid having this series in the listbox.

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Muso · 2022-02-22 12:58

Quote from: wp on February 21, 2022, 09:52:17 pmThese events have a
boolean parameter Skip which you can set to true if you want to avoid
having this series in the listbox.

I use the method already. But the use case here is that OnAddSeries is
not triggered. I open a dialog containing the TChartListBox and
depending on the settings the user do in this dialog, the
TChartListBox should display certain series. The connected chart
should not be changed. Therefore I need a way to show/hide series in
this particular TChartListBox without touching the chart, meaning
OnAddSeries will not fire.

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wp · 2022-02-22 15:34

You can manually re-populate the listbox by calling the TChartListBox
method Populate()(. See attached demo.

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Muso · 2022-02-22 22:30

Quote from: wp on February 22, 2022, 04:34:04 pmYou can manually re-
populate the listbox by calling the TChartListBox method Populate()(.
See attached demo.

Many thanks! Populate was what I was looking for. This works fine.