WPF/XAML – Binding of WindowChrome.CaptionHeight

Question

Theme/Generic.xaml of my WPF Custom Control MyBaseWindow looks like this:

<Style TargetType="{x:Type MyBaseWindowPath:MyBaseWindow}">
        …
        <Setter Property="WindowChrome.WindowChrome">
            <Setter.Value>
                <WindowChrome CaptionHeight="{Binding ActualHeight, ElementName=HeaderPanel}"
                              GlassFrameThickness="0"
                              CornerRadius="0" />
            </Setter.Value>
        </Setter>
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{x:Type MyBaseWindowPath:MyBaseWindow}">
                    …
                    <DockPanel x:Name="HeaderPanel">
                    …
                    </DockPanel>
                    …
                </ControlTemplate>
            </Setter.Value>
        </Setter>
</Style>

I would like to bind ActualHeight property of HeaderPanel element within ControlTemplate. Is it possible?

Another solution is use fixed height for WindowChrome.CaptionHeight and HeaderPanel.Height, but I prefer binding to exact height.

score 1 · Accepted Answer · answered Mar 27 '17 at 18:14

1

ActualHeight is not a DependencyProperty or an INotifyPropertyChanged, so you can't bind directly to it and expect more than a one-time read. You can set a trigger on it in a style.

Work-around includes:

Creating a property in your class (view side) that is either a DependencyProperty or an INotifyPropertyChanged property.
Registering for the SizeChanged event on the element you want to know the AbsoluteHeight on.
In the handler for the event, update the property you created.

A fancier implementation would use attached dependency properties that essentially do the same thing, but they would be a bit more general purpose.

answered Mar 27 '17 at 18:14

Berin Loritsch

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`ActualHeight` **is** a DependencyProperty. https://msdn.microsoft.com/en-us/library/system.windows.frameworkelement.actualheightproperty(v=vs.110).aspx – Vlad Feb 25 '18 at 01:22
@Vlad, I stand corrected, but for whatever reason you still can't do a OneWayToSource binding to let your ViewModel know how big something is on screen--necessary for fancy meters and such. – Berin Loritsch Feb 26 '18 at 15:17
I assume that the problem is following: `ActualHeight` is a read-only property, so Binding erroneously refuses to be created even with OneWayToSource mode. See this answer: https://stackoverflow.com/a/7227295/276994 – Vlad Feb 26 '18 at 17:28

score 0 · Answer 2 · edited Jun 14 '21 at 10:24

In 2021, my solution without binding was to assign a x:Name to the WindowChrome and change CaptionHeight value in Window_SizeChanged event:

private void Window_SizeChanged(object sender, SizeChangedEventArgs e)
{
    SessionWindowChrome.CaptionHeight = ActualHeight
       - SessionWindowChrome.ResizeBorderThickness.Top 
       - SessionWindowChrome.ResizeBorderThickness.Bottom;    
}

Take in account that i use ResizeBorderThickness variables too...

WPF/XAML – Binding of WindowChrome.CaptionHeight

2 Answers2