Articolo
11/18/2011

Lazy<T> Class

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Provides support for lazy initialization.

Inheritance Hierarchy

System.Object
System.Lazy<T>
System.Lazy<T, TMetadata>

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

Syntax

'Declaration
<ComVisibleAttribute(False)> _
<DebuggerDisplayAttribute("ThreadSafetyMode={Mode}, IsValueCreated={IsValueCreated}, IsValueFaulted={IsValueFaulted}, Value={ValueForDebugDisplay}")> _
Public Class Lazy(Of T)

[ComVisibleAttribute(false)]
[DebuggerDisplayAttribute("ThreadSafetyMode={Mode}, IsValueCreated={IsValueCreated}, IsValueFaulted={IsValueFaulted}, Value={ValueForDebugDisplay}")]
public class Lazy<T>

Type Parameters

T
Specifies the type of object that is being lazily initialized.

The Lazy<T> type exposes the following members.

Constructors

	Name	Description
	Lazy<T>()	Initializes a new instance of the Lazy<T> class. When lazy initialization occurs, the default constructor of the target type is used.
	Lazy<T>(Boolean)	Initializes a new instance of the Lazy<T> class. When lazy initialization occurs, the default constructor of the target type and the specified initialization mode are used.
	Lazy<T>(Func<T>)	Initializes a new instance of the Lazy<T> class. When lazy initialization occurs, the specified initialization function is used.
	Lazy<T>(LazyThreadSafetyMode)	Initializes a new instance of the Lazy<T> class that uses the default constructor of T and the specified thread safety mode.
	Lazy<T>(Func<T>, Boolean)	Initializes a new instance of the Lazy<T> class. When lazy initialization occurs, the specified initialization function and initialization mode are used.
	Lazy<T>(Func<T>, LazyThreadSafetyMode)	Initializes a new instance of the Lazy<T> class that uses the specified initialization function and thread safety mode.

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Properties

	Name	Description
	IsValueCreated	Gets a value that indicates whether a value has been created for this Lazy<T> instance.
	Value	Gets the lazily initialized value of the current Lazy<T> instance.

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Methods

	Name	Description
	Equals(Object)	Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
	Finalize	Allows an object to try to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection. (Inherited from Object.)
	GetHashCode	Serves as a hash function for a particular type. (Inherited from Object.)
	GetType	Gets the Type of the current instance. (Inherited from Object.)
	MemberwiseClone	Creates a shallow copy of the current Object. (Inherited from Object.)
	ToString	Creates and returns a string representation of the Lazy<T>.Value property for this instance. (Overrides Object.ToString().)

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Remarks

Lazy initialization occurs the first time the Lazy<T>.Value property is accessed.

Use an instance of Lazy<T> to defer the creation of a large or resource-intensive object or the execution of a resource-intensive task, particularly when such creation or execution might not occur during the lifetime of the program.

Version Information

Silverlight

Supported in: 5, 4

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

Thread Safety

By default, all public and protected members of the Lazy<T> class are thread safe and may be used concurrently from multiple threads. These thread-safety guarantees may be removed optionally and per instance, using parameters to the type's constructors.

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