How to setup Row/Column Definitions in Xamarin.Forms Xaml? - grid

Question

I managed to setup rows and columns from the code but couldn't move this settings to xaml:
grid.RowDefinitions = new RowDefinitionCollection {
new RowDefinition { Height = new GridLength(1, GridUnitType.Star) }
};
grid.ColumnDefinitions = new ColumnDefinitionCollection {
new ColumnDefinition { Width = new GridLength(1, GridUnitType.Star) }
};
The following doesn't work:
<Grid x:Name="grid" VerticalOptions="FillAndExpand" HorizontalOptions="FillAndExpand">
<Grid.RowDefinitions>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
...
</Grid>
From the documentation I managed to fetch only c# implementation

Answer 1

I also get the same behaviour (does not fill and expand) for a grid with a single cell (1 row / column, although I am not sure why we would ever need a grid with a single cell full size of screen), but it seems to work fine for a 2 x 2, 3 x 3 cell grid (have not tried others yet).
The Height="" and Width="" attributes are required in Xamarin Forms although I "think" they are not needed in WPF as the default assumes this is the case.
<ContentPage.Content>
<Grid VerticalOptions="FillAndExpand" HorizontalOptions="FillAndExpand">
<Grid.RowDefinitions>
<RowDefinition Height="*"></RowDefinition>
<RowDefinition Height="*"></RowDefinition>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"></ColumnDefinition>
<ColumnDefinition Width="*"></ColumnDefinition>
</Grid.ColumnDefinitions>
<Button Grid.Row="0" Grid.Column="0" Text="1"></Button>
<Button Grid.Row="1" Grid.Column="1" Text="2"></Button>
</Grid>
</ContentPage.Content>

Answer 2

Here is a sample
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="*" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Label Text="Top Left" Grid.Row="0" Grid.Column="0" />
<Label Text="Top Right" Grid.Row="0" Grid.Column="1" />
<Label Text="Bottom Left" Grid.Row="1" Grid.Column="0" />
<Label Text="Bottom Right" Grid.Row="1" Grid.Column="1" />
</Grid>