#1,180 – By Default, FrameworkElement Doesn’t Have Desired Size

If you create a custom control that derives from FrameworkElement, the control won’t by default have any particular desired size.  You can see this by setting alignment properties on a simple custom control without also setting explicit Width and Height.

    <Grid ShowGridLines="True">
        <Grid.RowDefinitions>
            <RowDefinition/>
            <RowDefinition/>
        </Grid.RowDefinitions>

        <loc:MyFrameworkElement HorizontalAlignment="Center"
                                VerticalAlignment="Top"/>
        <loc:MyFrameworkElement Grid.Row="1" Margin="20,10"/>
    </Grid>

You can see in the designer that the first instance of MyFrameworkElement is not visible, because it has no size.

1180-001

A custom control will typically define its desired size based on its content.  In the example above, the custom control hasn’t specified any desired size, size the control has a size of (0,0) and disappears.

 

About Sean
Software developer in the Twin Cities area, passionate about .NET technologies. Equally passionate about my own personal projects related to family history and preservation of family stories and photos.

One Response to #1,180 – By Default, FrameworkElement Doesn’t Have Desired Size

  1. Pingback: Dew Drop – October 15, 2014 (#1877) | Morning Dew

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