How to simulate Windows Theme behaviour when TComboBox uses csOwnerDrawFixed or csOwnerDrawVariable?

Question

A very easy way to show different string values than the Items is to set the Style property from csDropDown to csOwnerDrawFixed as Andreas Rejbrand has answered a few years ago.

The thing is: as soon as you do that, you loose Windows Theming support.
The same limitation applies to using csOwnerDrawVariable

These two Style values get translated into adding the CBS_OWNERDRAWFIXED or CBS_OWNERDRAWVARIABLE (in addition to CBS_DROPDOWNLIST) styles of the Windows COMBOBOX control.

In turn, CBS_OWNERDRAWFIXED or CBS_OWNERDRAWVARIABLE cause you to instantly loose the Windows theming support.

When you do full custom painting like a colour picker, that is all fine. But when you only want to replace the drawn text, it is not.

The Windows COMBOBOX control does not seem to have a way around this, so I'm wondering: how can you simulate the Windows theming from Delphi?

I assume it has to do with DrawThemedBackground, but it has been a while since I've done serious Delphi Control work, so any pointers on how to get started there are fine too (even if they invalidate my assumption).

Answer 1

Some links if people actually want to try this (you probably shouldn't as it is way too much work).

• Problem with drawing custom Windows controls
• Draw a themed combo box
• Parts and States of Standard Controls and Windows
• Biggest Vista UI change: dropdown lists now look like buttons
• How best to create a TPanel with a close 'cross' button in the top right?
• How i can use different text of item text in ComboBox in Delphi
• TComboBox TOwnerDrawState OnDrawItem odComboBoxEdit
• How a Combobox with the csOwnerDrawFixed Style can behave like the csDropDown style?