Question

I create a GridSplitter across the 3 rows that I have in my grid like this:

<GridSplitter Grid.Row="0" Grid.Column="1" Background="Yellow"
              HorizontalAlignment="Stretch" VerticalAlignment="Stretch"
              Width="Auto" Height="Auto" ResizeDirection="Columns"
              Grid.RowSpan="3" ...

However, it’s conceivable that I might add another row to my grid at a later stage, and I don’t really want to go back and update all of my rowspans.

My first guess was Grid.RowSpan="*", but that doesn’t compile.

Answer 1

You can bind to the RowDefinitions.Count but would need to update the binding when adding rows manually.

Edit: Only semi-manually in fact
Xaml:

<StackPanel Orientation="Vertical">
    <Grid Name="GridThing">
        <Grid.ColumnDefinitions>
            <ColumnDefinition/>   
            <ColumnDefinition/>         
            </Grid.ColumnDefinitions>
            <Grid.RowDefinitions>
                <RowDefinition />
            <RowDefinition />   
            </Grid.RowDefinitions>
            <Grid.Children>
                <Button Content="TopRight" Grid.Row="0" Grid.Column="1"/>
                <Button Content="LowerRight" Grid.Row="1" Grid.Column="1"/>
            <Button Content="Span Rows" Name="BSpan" Grid.RowSpan="{Binding RelativeSource={RelativeSource AncestorType=Grid}, Path=RowDefinitions.Count, Mode=OneWay}"/>
        </Grid.Children>
        </Grid>
    <Button Click="Button_Click" Content="Add Row" />
</StackPanel>

Code:

    private void Button_Click(object sender, RoutedEventArgs e)
    {
        GridThing.RowDefinitions.Add(new RowDefinition() { Height = new GridLength(20) });
        foreach (FrameworkElement child in GridThing.Children)
        {
            BindingExpression exp = child.GetBindingExpression(Grid.RowSpanProperty);
            if (exp != null)
            {
                exp.UpdateTarget();
            }
        }
    }