How to keep grid cell height and width the same

Question

I need to keep the Grid cell height = width when resizing.

The working code using a viewBox:

  <Viewbox>
        <Grid>
            <Grid.RowDefinitions>
                    <RowDefinition Height="1*"/>
                    <RowDefinition Height="1*"/>
                </Grid.RowDefinitions>
                <Grid.ColumnDefinitions>
                    <ColumnDefinition Width="Auto"/>
                    <ColumnDefinition Width="Auto"/>
                </Grid.ColumnDefinitions>
                <Label Grid.Row="0" Grid.Column="0" Background="Black" Width="{Binding RelativeSource={RelativeSource Self}, Path=ActualHeight}"></Label>
                <Label Grid.Row="1" Grid.Column="0" Background="Gray" Width="{Binding RelativeSource={RelativeSource Self}, Path=ActualHeight}"></Label>
                <Label Grid.Row="0" Grid.Column="1" Background="Gray" Width="{Binding RelativeSource={RelativeSource Self}, Path=ActualHeight}"></Label>
                <Label Grid.Row="1" Grid.Column="1" Background="Black" Width="{Binding RelativeSource={RelativeSource Self}, Path=ActualHeight}"></Label>
            </Grid>
        </Viewbox>

Thank's to H.B. for the idea to use a viewBox! :)

Answer 1

The "proper" way to do this is probably using the shared-size features of the Grid control, but this sadly prevents stretching the whole grid. e.g.

<Grid Grid.IsSharedSizeScope="True">
    <Grid.ColumnDefinitions>
        <ColumnDefinition SharedSizeGroup="A"/>
        <ColumnDefinition SharedSizeGroup="A"/>
    </Grid.ColumnDefinitions>
    <Grid.RowDefinitions>
        <RowDefinition SharedSizeGroup="A"/>
        <RowDefinition SharedSizeGroup="A"/>
    </Grid.RowDefinitions>
    <Label Grid.Row="0" Grid.Column="0" Background="Red"   Content="Lorem"/>
    <Label Grid.Row="1" Grid.Column="0" Background="White" Content="Lorem ipsum"/>
    <Label Grid.Row="0" Grid.Column="1" Background="White" Content="Lorem ipsum dolor"/>
    <Label Grid.Row="1" Grid.Column="1" Background="Red"   Content="Lorem ipsum dolor sit"/>
</Grid>

One could place this in a Viewbox but the resize behavior of that is probably not what you want, since it zooms the contents. Maybe you can find a way to make this usable in your context.