doc/articles/features/windows-ui-succinct-syntax.md
Uno supports the succinct syntax WinUI XAML language feature that allows the initialization of collection-type properties (including read-only properties) using element attribute syntax.
The code below has the same functionality as the code shown above with the original syntax. It creates a grid and defines five different rows and columns, each with their own specific height/width, and adds them to the Grid.
<Grid ColumnDefinitions="1*, 2*, Auto, *, 300"
RowDefinitions="1*, Auto, 25, 14, 20">
</Grid>
The code below has the same functionality as the code shown above with the original syntax, but uses the ColumnDefinition and RowDefinition content property assignments to write it in the following way.
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition>1*</ColumnDefinition>
<ColumnDefinition>2*</ColumnDefinition>
<ColumnDefinition>Auto</ColumnDefinition>
<ColumnDefinition>*</ColumnDefinition>
<ColumnDefinition>300</ColumnDefinition>
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition>1*</RowDefinition>
<RowDefinition>Auto</RowDefinition>
<RowDefinition>25</RowDefinition>
<RowDefinition>14</RowDefinition>
<RowDefinition>20</RowDefinition>
</Grid.RowDefinitions>
</Grid>
See the WinUI documentation for more details.