Gets or sets a value that indicates whether the property binds two-way by default.
Assembly: PresentationFramework (in PresentationFramework.dll)
XMLNS for XAML: http://schemas.microsoft.com/winfx/2006/xaml/presentation, http://schemas.microsoft.com/netfx/2007/xaml/presentation
Property ValueType: System.Boolean
true if the dependency property on which this metadata exists binds two-way by default; otherwise, false. The default is false.
The metadata has already been applied to a dependency property operation, so that metadata is sealed and properties of the metadata cannot be set.
In absence of this property being true, binding updates are one-way by default, based on the default behavior of the Binding constructors or equivalent XAML syntax.
In existing elements, you will usually find this property set to true in metadata for dependency properties that both report state and are modifiable by user action, for example Selector.IsSelected.
This property only reports the default binding update characteristics of the dependency property in general. Any binding set to this property on an instance can locally set the Mode property of the binding and change this default.
Properties on any derived classes of PropertyMetadata are typically defined in the object model as read-write. This is so they can be adjusted after initialization of the instance. However, after the metadata is consumed as part of a call to Register, AddOwner, or OverrideMetadata, the property system will seal that metadata instance and properties that convey the specifics of the metadata are now considered immutable. Attempting to set this property after IsSealed is true on this metadata instance will raise an exception.
The following example obtains the default metadata from various dependency property fields, queries the value of various FrameworkPropertyMetadata properties on it, and uses the information to populate a table to implement a "metadata browser".
pm = dp.GetMetadata(dp.OwnerType) ... Dim fpm As FrameworkPropertyMetadata = TryCast(pm, FrameworkPropertyMetadata) If fpm IsNot Nothing Then AffectsArrange.Text = If((fpm.AffectsArrange), "Yes", "No") AffectsMeasure.Text = If((fpm.AffectsMeasure), "Yes", "No") AffectsRender.Text = If((fpm.AffectsRender), "Yes", "No") [Inherits].Text = If((fpm.Inherits), "Yes", "No") IsDataBindingAllowed.Text = If((fpm.IsDataBindingAllowed), "Yes", "No") BindsTwoWayByDefault.Text = If((fpm.BindsTwoWayByDefault), "Yes", "No")