FrameworkElement Class

Updated: July 2008

Provides a WPF framework-level set of properties, events, and methods for Windows Presentation Foundation (WPF) elements. This class represents the provided WPF framework-level implementation built on the WPF core-level APIs defined by UIElement.

Namespace:  System.Windows
Assembly:  PresentationFramework (in PresentationFramework.dll)
XMLNS for XAML: http://schemas.microsoft.com/winfx/2006/xaml/presentation, http://schemas.microsoft.com/netfx/2007/xaml/presentation

[RuntimeNamePropertyAttribute(L"Name")]
[StyleTypedPropertyAttribute(Property = L"FocusVisualStyle", StyleTargetType = typeof(Control))]
[XmlLangPropertyAttribute(L"Language")]
public ref class FrameworkElement : public UIElement, 
	IFrameworkInputElement, IInputElement, ISupportInitialize
<FrameworkElement .../>

FrameworkElement is the connecting point between WPF framework-level element classes and the WPF core-level set of UIElement presentation services. For more information about these concepts, see WPF Architecture.

FrameworkElement extends UIElement and adds the following capabilities:

  • Layout system definitionFrameworkElement provides specific WPF framework-level implementations for certain methods that were defined as virtual members in UIElement. Most notably, FrameworkElement seals certain WPF core-level layout overrides, and instead provides a WPF framework-level equivalent that derived classes should override instead. For example, FrameworkElement seals ArrangeCore but provides ArrangeOverride. These changes reflect the fact that at the WPF framework-level there is a full layout system in place that can render any FrameworkElement derived class. At the WPF core level, certain members that will structure a general WPF based layout solution are in place, but the actual engine of the layout system is not defined. For more information, see The Layout System.

  • The logical tree: The general WPF programming model is often expressed in terms of being a tree of elements. Support for expressing the tree of elements as a logical tree, and accompanying support for defining that tree in markup is implemented at the FrameworkElement level. Note however that FrameworkElement deliberately does not define a content model, and leaves that responsibility to derived classes. For more information, see Trees in WPF.

  • Object lifetime events: It is often useful to know when an element is initialized (the constructor is called) or when the element is first loaded into a logical tree. FrameworkElement defines several events related to object lifetime that provide useful hooks for code-behind operations that involve elements, such as adding more child elements. For more information, see Object Lifetime Events.

  • Support for data binding and dynamic resource references: The property-level support for data binding and resources is implemented by the DependencyProperty class and embodied in the property system, but the ability to resolve a member value that is stored as an Expression (the programming construct that underlies both data binding and dynamic resources) is implemented by FrameworkElement. For more information, see Data Binding Overview and Resources Overview.

  • Styles: FrameworkElement defines the Style property. However, FrameworkElement does not yet define support for templates, or support decorators. These features are introduced by control classes such as Control and ContentControl.

  • More animation support: Some animation support was already defined at the WPF core level, but FrameworkElement extends this by implementing BeginStoryboard and related members.

As can be seen from the class hierarchy, many WPF classes derive from FrameworkElement, either directly or through intermediate base classes such as Panel or Control.

If you intend to use FrameworkElement as a base class, you might want to first examine the existing derived classes. FrameworkElement provides support for a number of basic scenarios, but also lacks a number of features that are desirable for an "element" in the sense of a building block that you use to create user interface (UI) in Extensible Application Markup Language (XAML). For instance, a FrameworkElement does not define any true content model; FrameworkElement as a base class does not define a property that can create XAML child elements. In particular, you might want to look at Control and ContentControl.

System::Object
  System.Windows.Threading::DispatcherObject
    System.Windows::DependencyObject
      System.Windows.Media::Visual
        System.Windows::UIElement
          System.Windows::FrameworkElement
            Microsoft.Windows.Themes::BulletChrome
            Microsoft.Windows.Themes::ScrollChrome
            System.Windows.Controls::AccessText
            System.Windows.Controls::AdornedElementPlaceholder
            System.Windows.Controls::ContentPresenter
            System.Windows.Controls::Control
            System.Windows.Controls::Decorator
            System.Windows.Controls::Image
            System.Windows.Controls::InkCanvas
            System.Windows.Controls::ItemsPresenter
            System.Windows.Controls::MediaElement
            System.Windows.Controls::Page
            System.Windows.Controls::Panel
            System.Windows.Controls.Primitives::DocumentPageView
            System.Windows.Controls.Primitives::GridViewRowPresenterBase
            System.Windows.Controls.Primitives::Popup
            System.Windows.Controls.Primitives::TickBar
            System.Windows.Controls.Primitives::Track
            System.Windows.Controls::TextBlock
            System.Windows.Controls::ToolBarTray
            System.Windows.Controls::Viewport3D
            System.Windows.Documents::Adorner
            System.Windows.Documents::AdornerLayer
            System.Windows.Documents::DocumentReference
            System.Windows.Documents::FixedPage
            System.Windows.Documents::Glyphs
            System.Windows.Documents::PageContent
            System.Windows.Interop::HwndHost
            System.Windows.Shapes::Shape

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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.

.NET Framework

Supported in: 3.5, 3.0

Date

History

Reason

July 2008

Added new members: BindingGroup property, BindingGroupProperty field.

SP1 feature change.

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