DependencyProperty.RegisterReadOnly Method (String, Type, Type, PropertyMetadata, ValidateValueCallback)


Registers a read-only dependency property, with the specified property type, owner type, property metadata, and a validation callback.

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

public static DependencyPropertyKey RegisterReadOnly(
	string name,
	Type propertyType,
	Type ownerType,
	PropertyMetadata typeMetadata,
	ValidateValueCallback validateValueCallback


Type: System.String

The name of the dependency property to register.

Type: System.Type

The type of the property.

Type: System.Type

The owner type that is registering the dependency property.

Type: System.Windows.PropertyMetadata

Property metadata for the dependency property.

Type: System.Windows.ValidateValueCallback

A reference to a user-created callback that should perform any custom validation of the dependency property value beyond typical type validation.

Return Value

Type: System.Windows.DependencyPropertyKey

A dependency property key that should be used to set the value of a static read-only field in your class, which is then used to reference the dependency property later.

This method returns the type DependencyPropertyKey, whereas RegisterAttached returns the type DependencyProperty. Typically, the keys that represent read-only properties are not made public, because the keys can be used to set the dependency property value by calling SetValue(DependencyPropertyKey, Object). Your class design will affect your requirements, but it is generally recommended to limit the access and visibility of any DependencyPropertyKey to only those parts of your code that are necessary to set that dependency property as part of class or application logic. It is also recommended that you expose a dependency property identifier for the read-only dependency property, by exposing the value of DependencyPropertyKey.DependencyProperty as a public static readonly field on your class.

Read-only dependency properties are a fairly typical scenario. You can use the value of a read-only dependency property as the basis for other property system operations that take a dependency property, such as basing a Trigger on the dependency property in a style.

For more information on dependency property registration, see DependencyProperty.

Validation on a read-only dependency property might be less important. The nonpublic access level you specify for the key reduces the likelihood for arbitrary invalid input.

.NET Framework
Available since 3.0
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