How to apply theme to all controls automatically at design time?

[Joke]

The default design time theme is `office black`, is there any approaches to change default theme?

Set `telerik:StyleManager.Theme="xxx"` for each control is very troublesome.

[Stenly]

Hello Joke Huang,

Currently, in order to see a different theme in the designer, it would have to be applied on а control level by setting the StyleManager.Theme attached property. This is the case when using the Xaml assemblies and StyleManager to apply a theme. This is because the application-wide theme is evaluated at run-time.

As an alternative, what I could suggest would be to use the NoXaml assemblies and the Implicit Styles theming approach. This will allow you to change themes at design-time with only a few clicks.

With this being said, would it be possible to give this suggestion a try and let me know how it goes?

Regards,
Stenly
Progress Telerik