Cycle thru XAML/StyleManager themes programmatically?

[Rob A.]

I was wondering if it's possible to cycle thru "available" themes programmatically when using XAML/StyleManager approach?  I'd like to cycle thru whatever themes are supported in the XAML approach and display their names in a ComboBox for a user to select.

Cheers, Rob.

 

[Rob A.]

In addition, it seems when changing the StyleManager.Application theme in "real-time" the UI doesn't update with the new theme?

After reading this document: https://docs.telerik.com/devtools/wpf/styling-and-appearance/how-to/styling-apperance-themes-runtime

... it seems that this can't be achieved when using the XAML/StyleManager approach (only for NoXAML)?  So the only way to get the Theme to update is to re-start my application?

I'm hoping I missed something in the documentation as this seems like a rather significant draw back to XAML approach for Themes and probably should have been mentioned here: https://docs.telerik.com/devtools/wpf/styling-and-appearance/xaml-vs-noxaml

Thoughts?

Cheers, Rob.

[Martin Ivanov]

Hello Rob,

Indeed, the StyleManager theming mechanism doesn't support run-time application theme changes. This will work only NoXaml dlls and Implicit Styles. With StyleManager, you can change the theme only per control by setting the StyleManager.Theme attached property. However, this is not very convenient if you have multiple controls. Here is an example in code:

StyleManager.SetTheme(this.radControl, new FluentTheme());

I also included a note in the Xaml vs. NoXaml article about this and updated your Telerik points.

Regards,
Martin Ivanov
Progress Telerik

[Rob A.]

Disappointing, but Ok.  It does seem to work when opening a new RadWindow but not on the main windows which I'm assuming would need an InitializeComponent() call when they've already been initialized.

Thank you for adding this "gotcha" to the documentation ... it's certainly a "decision" trigger for anyone else considering which path to go down for Themes.  

As a work around I've implemented an application shutdown and restart ... not pretty but gets the job done.

Cheers, Rob.

[Martin Ivanov]

Hello Robin,

The StyleManager.ApplicationTheme attached property instructs the controls which theme style should be assigned to their Style property. Changing the application theme at runtime means that the StyleManager should know about all Telerik controls and go resetting their Style based on the new theme, which doesn't happen. When you initialize new controls after the application theme is changed, they use the styles from the new theme. This is why when you open a new RadWindow after the theme change, you see the new theme applied.

Regards,
Martin Ivanov
Progress Telerik