PropertyMetadata.PropertyChangedCallback Property

Gets or sets a reference to a PropertyChangedCallback implementation specified in this metadata.

Namespace:  System.Windows
Assembly:  WindowsBase (in WindowsBase.dll)

public PropertyChangedCallback PropertyChangedCallback { get; set; }

Property Value

Type: System.Windows.PropertyChangedCallback
A PropertyChangedCallback implementation reference.

ExceptionCondition
InvalidOperationException

Cannot set a metadata property once it is applied to a dependency property operation.

The callbacks in property metadata are not typically public members on the defining type, so the value of this property is not important for most scenarios that just consume an existing dependency property's metadata. One reason this property is exposed is so that metadata classes can perform their desired merge logic if both base metadata and overriding/adding metadata specify a PropertyChangedCallback. The default merge logic for is to maintain all PropertyChangedCallback implementations in a table and call each of them, with callbacks established by the deepest class in hierarchy running first.

PropertyChangedCallback is defined in the object model as read-write. This is so PropertyChangedCallback can be adjusted after initialization of the PropertyMetadata object itself. However, once the metadata is consumed as part of a call to Register, AddOwner, or OverrideMetadata, the property system will seal that metadata instance and the properties are now considered immutable. Attempting to set PropertyChangedCallback once IsSealed is true on this metadata instance will raise an exception.

.NET Framework

Supported in: 4.5, 4, 3.5, 3.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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