Let me start with stating that our themes are independent and does not rely on Windows settings or themes. You can still achieve the desired look though.
For the purpose you might use the fact that Outlook template has our Office 2013 Theme applied. It provides palette of colors that you might modify. Now you need the exact system colors being applied when Windows has HighContrast theme. For the purpose WPF exposes a swatch of colors via SystemColors
class. I attached a modified version of our Outlook template where I have shown how you might achieve such customization. Please check the attached image where the result is demonstrated. There are some limitations though that I'd like to point out:
1. In HighContrast themes there is default Color that get's applied on Foreground and Border of Disabled controls. For Office2013 theme we do not apply specific Color - GrayTextBrush
but change the Opacity of the elements when Disabled.
2. We do not have separate Brushes for White Foreground (the one used in Headers) and White Background. This means that changing the MainBrush that is the only one White Brush in the theme will get applied on both the Texts and Background.
3. RadRichTextBox that we use to edit the currently selected mail has hardcoded White Background that does not come from Office2013 theme. You'll need an implicit style that sets the Background property of the control to one of the Brushes that the theme exposes. For example:
As you already know this will make both the Background and the Foreground Black as they both point to MainBrush
so I'm suggesting that you add another setter for Foreground in this style where you hardcode the Foreground to White. This is again demonstrated in the attached project.
All these limitations can be workarounded but require additional work on your side - to restyle or retemplate some of the controls in the application to get the exact look of MS Outlook in HighContrast theme. Feel free to modify the attachment as you wish and let me know if there is anything else I can assist you with.
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