See Also: ColumnDefinitionCollection Members
App developers can specify Xamarin.Forms.GridUnitType values for the ColumnDefinition.Width property in XAML by nesting ColumnDefinition tags inside tags for the Grid.ColumnDefinitions collection property. The following example demonstrates setting three column widths to each of the three valid Xamarin.Forms.GridUnitType values:
XAML Example
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="*" />
<ColumnDefinition Width="100" />
</Grid.ColumnDefinitions>