Fix: Add TemplateBindings to BorderBrush and BorderThickness

[HedpE-]

Add TemplateBindings to BorderBrush and BorderThickness to SnackBar Style.

Fixes #3883

[nicolaihenriksen]

@HedpE- Thank you for the PR. The changes look fine to me! One thought though. In many cases, when I am manipulating the BorderBrush/BorderThickness of a bordered element, I also want/need control over the CornerRadius. We could consider adding a SnackBar.CornerRadius dependeny property of type Thickness.

The default style would then need an additional setter:

<Setter Property="CornerRadius" Value="3" />

And the value set in the ContentBorder should be changed to a template binding:

<Border x:Name="ContentBorder"
  ...
  CornerRadius="{TemplateBinding CornerRadius}"
  ...
</Border>

[HedpE-]

Yes I agree, it's a fiine addition, should I do another PR for the CornerRadius?

[nicolaihenriksen]

Yes I agree, it's a fiine addition, should I do another PR for the CornerRadius?

Adding it here as you did is fine I believe 👍