Changing Theme at runtime

[f4n0]

Describe the bug
Hi,
I have 2 variables of type "Theme", one containing the dark theme and the other the light one.
I've seen that if I set the theme on the main layout it all works, but If I want to change the theme via cascading parameter it doesn't work as I expected.

The sample from the documentation works as expected, but in my case, I'm assigning another theme to the parameter, and, for some reason, it won't work.

Here's a screenshot

The true branch of the condition won't work, the other works as expected!

Am I missing something?

[stsrki]

You mean if you assign it with Theme = options.Theme; then it will not work?

[f4n0]

yes

[f4n0]

BlazorApp1.zip

Here's an example:
In the menu, there is a checkbox that will trigger the dark theme or light.
Going dark is working, Disable it will not work!

Hope it helps!

[StefanOssendorf]

@f4n0 Your example won't work because of the cascading value. You can't replace it from a child which receives the cascading value.
For more information see this: https://chrissainty.com/understanding-cascading-values-and-cascading-parameters/

[f4n0]

so, I have to replace property by property (because I haven't access to the parent)?

[StefanOssendorf]

Yes. Or you move the functionality to the parent.

[f4n0]

I will give it a shot!
thank you

[stsrki]

I must admit I have completely forgotten that changing the cascaded reference is not allowed. Thanks, @StefanOssendorf for the link.

I think we can introduce a new API to the ThemeProvider that can change the theme. Example ThemeProvider.SetTheme( newThemeObject ).

[f4n0]

that would be so nice!

[David-Moreira]

@stsrki let's treat this as a current limitation and as a future feature then? Can you update the issue accordingly?