[WPF] Grid: set height * of row from Code Behind

Question

Hi,

I have this definition:

<Grid Height="Auto" Width="Auto" Name="MainGrid">

<Grid.RowDefinitions>

<RowDefinition Height="auto" />

<RowDefinition Height="*" />

<RowDefinition Height="2"/>

<RowDefinition Height="auto" />

<RowDefinition Height="35" />

</Grid.RowDefinitions>

....

The MainGrid.RowDefinitions[1].Height is *

How can I set the height of the Row from CodeBehind?

The code should be:

MainGrid.RowDefinitions[1].Height = new GridLength(??, GridUnitType.Star);

but where there is "??" what is the correct value?

Thanks.