React-like contexts

[handicraftsman]

In React Context is an object which contains some value and exports a Provider - an element which provides value to all children, overridding parents' values, and "users" - functions which get value of the nearest provider of given type. On context update users are updated too.

Would be nice in conjunction with control themes as in #2769 .

This might look like below; sorry if i have any mistakes - i am not good enough in xaml, although i hope you get the idea.

class ThemeContext : Context {
  public Color PrimaryColor { get; set; }
}

<ThemeContext PrimaryColor="#123456">
  <ContextUser Context={x:Type} x:Name="theme">
    <SomeElement Color={x:Bind theme.PrimaryColor} />
  </ContextUser>
</ThemeContext>

[kekekeks]

How exactly is it different from DynamicResource?

<ContentControl>
     <ContentControl.Resources>
           <Color x:Key="ThemePrimaryColor">#123456</Color>
     </ContentControl.Resources>
     <SomeElement Color="{DynamicResource ThemePrimaryColor}"/>
</ContentControl>

Also, you can achieve contexts via inherited attached properties.

e. g.

class ThemeContext
{
      public Color PrimaryColor { get; set; }
      public static AvaloniaProperty CurrentProperty = AvaloniaProperty.RegisterAttached(...
      ... attached getter and setter here ...
}

<ContentControl>
     <local:ThemeContext.Current>
          <local:ThemeContext Color="#123456"/>
     </local:ThemeContext.Current>
     <SomeElement Color="{Binding (local:ThemeContext.Current).Color, RelativeSource={RelativeSource Self}}"/>
</ContentControl>

[kekekeks]

Another way would be a class inheriting from ContentControl, e. g.

class ThemeContext : ContentControl
{
      public Color PrimaryColor { get; set; }
}

<local:ThemeContext PrimaryColor="#123456">

    <SomeElement Color="{Binding $parent[local:ThemeContext].PrimaryColor}" />

</ThemeContext>

[handicraftsman]

Hmm, nice. Sorry for asking without knowing that.