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Interface IPublishedValueFallback

Provides a fallback strategy for getting IPublishedElement values.

Namespace: Umbraco.Core.Models.PublishedContent

Assembly: Umbraco.Core.dll

Syntax

public interface IPublishedValueFallback

Methods

TryGetValue(IPublishedContent, String, String, String, Fallback, Object, out Object, out IPublishedProperty)

Tries to get a fallback value for a published content property.

Declaration

bool TryGetValue(IPublishedContent content, string alias, string culture, string segment, Fallback fallback, object defaultValue, out object value, out IPublishedProperty noValueProperty)

Parameters

Type	Name	Description
IPublishedContent	content	The published element.
System.String	alias	The property alias.
System.String	culture	The requested culture.
System.String	segment	The requested segment.
Fallback	fallback	A fallback strategy.
System.Object	defaultValue	An optional default value.
System.Object	value	The fallback value.
IPublishedProperty	noValueProperty	The property that does not have a value.

Returns

Type	Description
System.Boolean	A value indicating whether a fallback value could be provided.

Remarks

This method is called whenever getting the property value for the specified alias, culture and segment, either returned no property at all, or a property with HasValue(culture, segment) being false.

In an IPublishedContent, because walking up the tree is possible, the content itself may not even have a property with the specified alias, but such a property may exist up in the tree. The noValueProperty parameter is used to return a property with no value. That can then be used to invoke a converter and get the converter's interpretation of "no value".

TryGetValue(IPublishedElement, String, String, String, Fallback, Object, out Object)

Tries to get a fallback value for a published element property.

Declaration

bool TryGetValue(IPublishedElement content, string alias, string culture, string segment, Fallback fallback, object defaultValue, out object value)

Parameters

Type	Name	Description
IPublishedElement	content	The published element.
System.String	alias	The property alias.
System.String	culture	The requested culture.
System.String	segment	The requested segment.
Fallback	fallback	A fallback strategy.
System.Object	defaultValue	An optional default value.
System.Object	value	The fallback value.

Returns

Type	Description
System.Boolean	A value indicating whether a fallback value could be provided.

Remarks

This method is called whenever getting the property value for the specified alias, culture and segment, either returned no property at all, or a property with HasValue(culture, segment) being false.

It can only fallback at element level (no recurse).

TryGetValue(IPublishedProperty, String, String, Fallback, Object, out Object)

Tries to get a fallback value for a property.

Declaration

bool TryGetValue(IPublishedProperty property, string culture, string segment, Fallback fallback, object defaultValue, out object value)

Parameters

Type	Name	Description
IPublishedProperty	property	The property.
System.String	culture	The requested culture.
System.String	segment	The requested segment.
Fallback	fallback	A fallback strategy.
System.Object	defaultValue	An optional default value.
System.Object	value	The fallback value.

Returns

Type	Description
System.Boolean	A value indicating whether a fallback value could be provided.

Remarks

This method is called whenever property.Value(culture, segment, defaultValue) is called, and property.HasValue(culture, segment) is false.

It can only fallback at property level (no recurse).

At property level, property.GetValue() does not implement fallback, and one has to get property.Value() or property.Value{T}() to trigger fallback.

Note that culture and segment may not be contextualized, so the variant context should be used to contextualize them (see our default implementation in the web project.

TryGetValue<T>(IPublishedContent, String, String, String, Fallback, T, out T, out IPublishedProperty)

Tries to get a fallback value for a published content property.

Declaration

bool TryGetValue<T>(IPublishedContent content, string alias, string culture, string segment, Fallback fallback, T defaultValue, out T value, out IPublishedProperty noValueProperty)

Parameters

Type	Name	Description
IPublishedContent	content	The published element.
System.String	alias	The property alias.
System.String	culture	The requested culture.
System.String	segment	The requested segment.
Fallback	fallback	A fallback strategy.
T	defaultValue	An optional default value.
T	value	The fallback value.
IPublishedProperty	noValueProperty	The property that does not have a value.

Returns

Type	Description
System.Boolean	A value indicating whether a fallback value could be provided.

Type Parameters

Name	Description
T	The type of the value.

Remarks

This method is called whenever getting the property value for the specified alias, culture and segment, either returned no property at all, or a property with HasValue(culture, segment) being false.

In an IPublishedContent, because walking up the tree is possible, the content itself may not even have a property with the specified alias, but such a property may exist up in the tree. The noValueProperty parameter is used to return a property with no value. That can then be used to invoke a converter and get the converter's interpretation of "no value".

TryGetValue<T>(IPublishedElement, String, String, String, Fallback, T, out T)

Tries to get a fallback value for a published element property.

Declaration

bool TryGetValue<T>(IPublishedElement content, string alias, string culture, string segment, Fallback fallback, T defaultValue, out T value)

Parameters

Type	Name	Description
IPublishedElement	content	The published element.
System.String	alias	The property alias.
System.String	culture	The requested culture.
System.String	segment	The requested segment.
Fallback	fallback	A fallback strategy.
T	defaultValue	An optional default value.
T	value	The fallback value.

Returns

Type	Description
System.Boolean	A value indicating whether a fallback value could be provided.

Type Parameters

Name	Description
T	The type of the value.

Remarks

This method is called whenever getting the property value for the specified alias, culture and segment, either returned no property at all, or a property with HasValue(culture, segment) being false.

It can only fallback at element level (no recurse).

TryGetValue<T>(IPublishedProperty, String, String, Fallback, T, out T)

Tries to get a fallback value for a property.

Declaration

bool TryGetValue<T>(IPublishedProperty property, string culture, string segment, Fallback fallback, T defaultValue, out T value)

Parameters

Type	Name	Description
IPublishedProperty	property	The property.
System.String	culture	The requested culture.
System.String	segment	The requested segment.
Fallback	fallback	A fallback strategy.
T	defaultValue	An optional default value.
T	value	The fallback value.

Returns

Type	Description
System.Boolean	A value indicating whether a fallback value could be provided.

Type Parameters

Name	Description
T	The type of the value.

Remarks

This method is called whenever property.Value{T}(culture, segment, defaultValue) is called, and property.HasValue(culture, segment) is false.

It can only fallback at property level (no recurse).

At property level, property.GetValue() does not implement fallback, and one has to get property.Value() or property.Value{T}() to trigger fallback.