如何使用xaml-xamarin.forms用布局填充屏幕？

我有一个网格，我想让它填满屏幕。 例如，我可以使用水平选项吗

  <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
        </Grid.RowDefinitions>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="Auto"/>
            <ColumnDefinition Width="Auto"/>
            <ColumnDefinition Width="Auto"/>
        </Grid.ColumnDefinitions>

        <Button Image="imgteste.png" Grid.Row="0" Grid.Column="0"></Button>
        <Label Text="User name:" Grid.Row="0" Grid.Column="1"></Label>
        <Label Text="User name:" Grid.Row="1" Grid.Column="0"></Label>
        <Label Text="User name:" Grid.Row="1" Grid.Column="1"></Label>
    </Grid>

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您需要像您所想的那样添加

水平选项

和

垂直选项

<Grid HorizontalOptions="Fill"
      VerticalOptions="Fill">
    <Grid.RowDefinitions>
        <RowDefinition Height="Auto"/>
        <RowDefinition Height="Auto"/>
        <RowDefinition Height="Auto"/>
    </Grid.RowDefinitions>
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="Auto"/>
        <ColumnDefinition Width="Auto"/>
        <ColumnDefinition Width="Auto"/>
    </Grid.ColumnDefinitions>

    <Button Image="imgteste.png" Grid.Row="0" Grid.Column="0"></Button>
    <Label Text="User name:" Grid.Row="0" Grid.Column="1"></Label>
    <Label Text="User name:" Grid.Row="1" Grid.Column="0"></Label>
    <Label Text="User name:" Grid.Row="1" Grid.Column="1"></Label>
</Grid>

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非常感谢