Binding to ActualWidth does not work

Rich_McGuire_5086 0
Viewed 22300

In a Silverlight 3.0 application I'm attempting to create a rectangle in a canvas and have it stretch the whole width of the canvas. I have attempted to do this by binding to the ActualWidth property of a parent container (seem sample below), however while I don't see any binding errors the value is not being bound. The rectangle is not visible as its width is zero. In addition tried binding to the ActualWidth of the canvas that contains my rectangle but this made no difference.

I did find this bug logged on Microsoft Connect but there were no workarounds listed.

Has anyone been able to solve this issue or can they point to solution?

Edit: The original code sample was not accurate of what I'm trying to achieve, updated for more clarity.

<UserControl>
    <Border BorderBrush="White"
            BorderThickness="1"
            CornerRadius="4"
            HorizontalAlignment="Center">
        <Grid x:Name="GridContainer">
            <Rectangle Fill="Aqua"
                       Width="150"
                       Height="400" />
            <Canvas>
                <Rectangle Width="{Binding Path=ActualWidth, ElementName=GridContainer}"
                           Height="30"
                           Fill="Red" />
            </Canvas>

            <StackPanel>
                <!-- other elements here -->
            </StackPanel>
        </Grid>
    </Border>
</UserControl>
actualwidth silverlight
8 Answers

Based on KeithMahoney's answer, it works fine on my UWP App and solves my problem. However, I cannot see my control in Design time because both the initial values of ActualWidthValue and ActualHeightValue are not provided in Design time. Although it works fine in running time, it is inconvenient for designing the layout of my control. With a little modification, this problem can be solved.

  1. In his c# code for both properties ActualWidthValue and ActualHeightValue, add

    set {;}

    to let us can provide dummy values from XAML code. Although it is no use for running time, it can be used for design time.

  2. In the declaration of Resources of his XAML code, provide c:ActualSizePropertyProxy suitable values for ActualWidthValue and ActualHeightValue such as

    ActualHeightValue="800" ActualWidthValue="400"

    Then it will show you a 400x800 control in design time.

user_43784430
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