Property

Name
Gap

Attached Property

Name
Flex

Example

<dev:FlexRowPanel Gap="8">
    <Border dev:FlexRowPanel.Flex="1" Background="Gray" />
    <Border dev:FlexRowPanel.Flex="3" Background="DimGray" />
</dev:FlexRowPanel>

NOTE

Children are arranged in a single row and share the available width in proportion to their Flex value (default 1), like CSS flex-grow. Each child fills the full height.

Demo

you can run demo and see this feature.