FrameworkElement.ActualWidth Property
Gets the rendered width of this element. This is a dependency property.
Assembly: PresentationFramework (in PresentationFramework.dll)
This property is a calculated value based on other width inputs, and the layout system. The value is set by the layout system itself, based on an actual rendering pass, and may therefore lag slightly behind the set value of properties such as Width that are the basis of the input change.
Because ActualWidth is a calculated value, you should be aware that there could be multiple or incremental reported changes to it as a result of various operations by the layout system. The layout system may be calculating required measure space for child elements, constraints by the parent element, and so on.
Although you cannot set this property from XAML, you can base a Trigger upon its value in a style.
Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003
The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.