how (and where) do I get actual ColumnDefinition Width="*" - xaml

Question

Short version of what I'm trying to accomplish.
Have a scrollable grid with a button.
Once button is pressed inject two buttons to the right of the existing row content and scroll the content horizontally to the left so that the right edge of the second button injected into the layout is aligned with the right edge of the screen.
Longer version describing the solution tried and the problems encountered:
I have a custom control (grid inside a scrollview) for a row in ListView.
Normally that grid is the same width as the device.
The star of the show is
< ColumnDefinition Width="*" x:Name="Star"/>
<Label Grid.Row="2" Grid.Column="3" Text="{Binding FacebookId}" x:Name="IDLabel"
Style="{StaticResource SmallLabelStyle}"
HorizontalOptions="Fill"
VerticalOptions="StartAndExpand" BackgroundColor="Red"
/> is assigned to that column later on in xaml
last two columns in the grid for delete and block buttons are initially zero width
<ColumnDefinition Width="0" x:Name="cdDelete"/>
<ColumnDefinition Width="0" x:Name="cdBlock"/>
and, hence, not shown (to have the * column hosting the label to be sized properly, because, besides the label, there is a thumbnail, a button and spacing columns present in the grid)
prior to those two there is a column for a button that changes the
columns width and scroll the expanded grid within the scrollview.
So I need some way to replace the gridLength for ColumnDefinition "*"
with the actual Width of that column for the device I run on.
this.cdBlock.Width = this.cdDelete.Width = Metrics.ThumbnailDiameter;
if (starwidth <= 0)
{
starwidth = this.IDLabel.Width;
^^^^^^^^^^^^^^^^^^^^^^^^^ problem is here: this returns the width the label fits into, not the actual width of the label highlighted (see red background above)
}
this.Star.Width = new GridLength(starwidth);
any suggestions how to deal with this?
Thanks.

Answer 1

It seems that ViewCell.ContextActions can be used to leverage
the platform table editing functionality
Which means the button exposing delete/block buttons would have to go
unless there is a way to show buttons for contextactions programmatically