IsValueCreated Property
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Lazy(Of T).IsValueCreated Property

.NET Framework (current version)
 

Gets a value that indicates whether a value has been created for this Lazy(Of T) instance.

Namespace:   System
Assembly:  mscorlib (in mscorlib.dll)

Public ReadOnly Property IsValueCreated As Boolean

Property Value

Type: System.Boolean

true if a value has been created for this Lazy(Of T) instance; otherwise, false.

When lazy initialization occurs for a Lazy(Of T) instance, it may result in either a value being created or an exception being thrown. If an exception is thrown, subsequent behavior of the Lazy(Of T) instance depends on whether exception caching is in effect. If the Lazy(Of T) instance was created by using a constructor that does not specify an initialization function, then exception caching is not in effect. A subsequent attempt to initialize the Lazy(Of T) might succeed, and after successful initialization the IsValueCreated property returns true. If the Lazy(Of T) instance was created with an initialization function (specified by the valueFactory parameter of the Lazy(Of T) constructor), then exception caching is controlled by the thread safety mode.

  • If the mode is LazyThreadSafetyMode.ExecutionAndPublication or LazyThreadSafetyMode.None, there is no second chance to initialize the Lazy(Of T) instance. If an exception occurs and is unhandled in the initialization function, that exception is cached and rethrown on subsequent accesses of the Lazy(Of T).Valueproperty. No value is created if an exception is thrown, so in such cases IsValueCreated returns false.

  • If the mode is LazyThreadSafetyMode.PublicationOnly, the first thread that succeeds in running the initialization function (or the default constructor) creates the value for the Lazy(Of T) instance. If the initialization function throws an exception on one thread, other threads can still try to initialize the Lazy(Of T) instance. Until the value is created, the IsValueCreated property returns false.

Universal Windows Platform
Available since 4.5
.NET Framework
Available since 4.0
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 4.0
Windows Phone Silverlight
Available since 8.0
Windows Phone
Available since 8.1
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