Coloring a stringgrid cell background(solved)
lazarus / 39-Graphics

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jbmckim · 2020-09-12 19:48

I get using OnPrepareCanvas to change cell color.  I do this
successfully in a couple places.

What's confusing me is a slightly different requirement.  I need to
allow the user to remove an alarm state (stringgrid cell, red
background) from a row by pushing a button. (Going cell by cell is
fine. The UI requirement is a column but that can be done cell by
cell.)

When this happens, there's no change to the cell value per se, just a
change to the background.  Therefore, OnPrepareCanvas doesn't fire. 
(The problem only occurs on reset as the initial alarm is thrown in
response to a new value being added to the cell in question.)

Therefore, how do I change the background color without modifying cell
value?

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wp · 2020-09-12 19:51

Call StringGrid.Invalidate to enforce a redraw of the grid; as a
consequence of this OnPrepareCanvas will be called for each cell
before it is painted.

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jbmckim · 2020-09-15 21:04

Outstanding.  Thanks.