Use this FireMonkey panel trick to change the color of a Delphi FireMonkey panel or make a FireMonkey panel transparent
I have seen some complex solutions to achieve this, but this is really quite easy to do. You just need one line of code.
Change the panel color
(Panel1.Controls[0] as TShape).Fill.Color := TAlphaColorRec.Red;
One line of code and we are done – BOOM
How does it work ?
This technique works because all FireMonkey panels own a TShape (usually a TRectangle) that covers the inside of the panel. In the above example, we are changing the color of that TShape to red
This also works for other panel variants that I have tried such as TCalloutPanel
More robust code
It ia possible (although I have never seen it) that Delphi might remove the TShape. So, lets modify the code to be more paranoid by first making sure that a TShape exists (hopefully it is the right one)
if (Panel1.ControlsCount >= 1) and (Panel1.Controls[0] is TShape) then (Panel1.Controls[0] as TShape).Fill.Color := TAlphaColorRec.Red; // uses System.UITypes
Want more – lets make the panel transparent
Now that you know the magic trick of the TPanel guts being a TShape, you can go further and manipulate the shape to make the panel transparent … like this
if (Panel1.ControlsCount >= 1) and (Panel1.Controls[0] is TShape) then (Panel1.Controls[0] as TShape).visible := FALSE;
Is this Future Proof ?
No – This is not guarenteed to work in future as Embaradero could remove this handy little TShape #0 feature. However, I think it is stable and I expect it to work in the long term (fingers crossed)
Alternatives
If you dont like that solution, here are some alternatives
- Add a TRect to the panel to show the color that you want. Thats pretty much the same technique that I use above, but you will feel more in control because you created it.
- Use Delphi Styles.
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About Me
- Oracle & Delphi software developer based in Perth, Western Australia
- Australian Delphi User Group – President
- Australian Oracle User Group – WA Committee Member
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Available to do remote presentations to user groups on Delphi and Oracle topics
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Scott Hollows - One Line At A Time 
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