[Bug] Global implicit style for ContentPage not being applied

[Cfun1]

Description

Global style for ContentPage is not working at all.

Steps to Reproduce

1. Sample application based on a Shell, with one or more ShellContent of a ContentPage.
2. Define a default global style for ContentPage.

   <Application.Resources>
        <ResourceDictionary>
            <Style TargetType="{x:Type ContentPage}">
                <Setter Property="BackgroundColor" Value="Black"/>
            </Style>

            <Style TargetType="{x:Type Label}">
                <Setter Property="TextColor" Value="red"/>
            </Style>
        </ResourceDictionary>
    </Application.Resources>

Expected Behavior

All ContentPage used in ShellContent (in this case) should have the background color black, and all Label used in application should have their text color red.

Actual Behavior

Label style is applied globally, but ContentPage style is not applied at all. (So it is probably not related with #10141)

Note

Global explicit style for ContentPage is not always working.

Basic Information

• Version with issue: 5.0.0-pre5
• Last known good version: NA
• IDE: VS2019

[Seuleuzeuh]

Same issue in the first 5.0 preview

[jsuarezruiz]

Attached a repro sample:
Issue12350.zip

[Saigronas]

Workaround mentioned in #10179 that works for me:

Add "ApplyToDerivedTypes="True" in style definition, ex:

<Style TargetType="ContentPage" ApplyToDerivedTypes="True">
fix copied from comment #10179 (comment)

[higun295]

@Saigronas It works for me. Thanks.

But, why should I add 'ApplyToDerivedTypes' to True ? I didn't understand fully yet..

I also found something. My problem was caused by Android Device's 'dark mode'.
Because of this, implicit global style wasn't working.

As a result, I cleared my problem. Thank you for everyone.

[Lucas-DeLorenzi]

Hi! I had the same problem, and I found the solution here...

Regarding the question of "why should I set 'ApplyToDerivedTypes' to True?" I believe that any class we create as a ContentPage is actually a derived class. It might be a mistake to think that we have created a ContentPage when, in fact, we are creating a XView that derives from a ContentPage.