Hi,

What is the recommended way of highlighting (by changing cell background color) certain cells based on there display value?

In Delphi I did the following:

* DefaultDrawing = False
* OnDrawDataCell I implemented the following.
Check for criteria, then set Brush.Color
Then call DefaultDrawDataCell

This saves me the trouble from having to manually draw everything like the background color, border, text etc...

Unfortunately this "easy" method is not possible with Lazarus, because DefaultDrawColumnCell doesn't paint the background (only text), it is done somewhere else (not sure where). Is this an oversight, or by design?

If by design, what is the recommended way of doing this?

Regards,
- Graeme -

--- El vie 22-ene-10, Graeme Geldenhuys escribi?:

The recommended way is using OnPrepareCanvas DbGrid event.

Using OnPrepareCanvas you don't have to draw anything, you get the column:tcolumn which is being painted as an argument and from there you get the field and can take decisions based on fields value, then you change dbgrid's canvas properties, for cell background you will have to adjust grid.canvas.brush.color, font changes can be made on grid.canvas.font, alignment, etc.

for borders one needs custom drawing and OnDrawColumnCell is needed, OnPrepareCanvas do not help here.

I think until now nobody noted the problem, probably this feature is not used too much. But IIRC, the background was supposed to be painted in OnDrawColumnCell and then you call DefaultDrawColumnCell, I might have mis understood how this works, I need a good test case.

If by design, what is the recommended way of doing this?

Although with OnPrepareCanvas we cover most of cases where this feature is needed I would like to make it Delphi compatible, if possible, please submit a bug report.

Regards, ? - Graeme -

Jesus Reyes A.

Encuentra las mejores recetas en Yahoo! Cocina.
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Il 22/01/2010 8.34, Jesus Reyes ha scritto:

Using OnPrepareCanvas you don't have to draw anything, you get the column:tcolumn which is being painted as an argument and from there you get the field and can take decisions based on fields value, then you change dbgrid's canvas properties, for cell background you will have to adjust grid.canvas.brush.color, font changes can be made on grid.canvas.font, alignment, etc.

I use OnPrepareCanvas in order to change color background and fonts of a grid. I encunter a problem with the font. I can set the font color but the Bold property does not work, any hint?
this is the code:

Canvas.Font.Bold:= True;
Canvas.Font.Color:= clSkyBlue;

The font are correctly drawn in clSkyBlue but are not set to bold. andrea

2010/1/22 Jesus Reyes :

The recommended way is using OnPrepareCanvas DbGrid event.

OK, thanks for the information.

for borders one needs custom drawing and OnDrawColumnCell is needed, OnPrepareCanvas do not help here.

Changing the border look is not really important to my example, so I'll ignore that for now.

Although with OnPrepareCanvas we cover most of cases where this feature is needed I would like to make it Delphi compatible, if possible, please submit a bug report.

OK, I'll create a bug report and add a test case project for you. Thanks for the quick responses.

--- El vie 22-ene-10, Andrea Mauri escribi?:

Strange but I confirmed the problem, if you use:

Canvas.Font.Style := Canvas.Font.Style + [fsBold];

it works, will try to find why is not working.

Jesus Reyes A.

Encuentra las mejores recetas en Yahoo! Cocina.
http://mx.mujer.yahoo.com/cocina/