Question

I’m trying to get the width and the height of a grid programmatically, In a UserControl.

Here is my XAML grid:

<Grid Name="BallGrid" Background="DarkBlue" Height="auto" Width="auto">
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="*"/>
    </Grid.ColumnDefinitions>
    <Grid.RowDefinitions>
        <RowDefinition Height="*"/>
    </Grid.RowDefinitions>
</Grid>

But both of these:

double width = BallGrid.ColumnDefinitions[0].ActualWidth;
double height = BallGrid.RowDefinitions[0].ActualHeight;

return 0,

and these

double width = BallGrid.ColumnDefinitions[0].Width.Value;
double height = BallGrid.RowDefinitions[0].Height.Value;

return both return 1.

I’d like to know the actual width, preferably in the same units as margin sizes. How can I get these values programmatically?

The column values are queried in a ProgessChanged method, that is called by a BackgroundWorker every 50 ms, maybe that makes a difference.

Answer 1

Usually you use ActualWidth/Height, here those properties are a bit lazy:

When you add or remove rows or columns, the ActualWidth for all ColumnDefinition elements and the ActualHeight of all RowDefinition elements becomes zero until Measure is called.

So you could probably call Measure manually or try to wait for it.