Core.Option<'T> Union (F#)

Artykuł
02/04/2013

Specifies the type of optional values, which you use when there might or might not be a value.

Namespace/Module Path: Microsoft.FSharp.Core

Assembly: FSharp.Core (in FSharp.Core.dll)

[<DefaultAugmentation(false)>]
[<StructuralEquality>]
[<StructuralComparison>]
type Option<'T> =
| None
| Some of 'T
 with
  interface IStructuralEquatable
  interface IComparable
  interface IComparable
  interface IStructuralComparable
  static member Some : 'T -> 'T option
  member this.IsNone :  bool
  member this.IsSome :  bool
  static member None :  'T option
  member this.Value :  'T
 end

Remarks

Use the constructors Some and None to create values of this type. Use the values in the Option module to manipulate values of this type, or pattern match against the values directly. None values appear as the value null to other .NET Framework languages. Instance methods of this type appear as static methods to other .NET Framework languages because of the use of null as a value representation.

For an overview of options, see Options (F#).

This type is named FSharpOption in compiled assemblies. If you are accessing the type from a language other than F#, or through reflection, use this name.

Instance Members

Member	Description
IsNone	Returns true if the option is a None value.
IsSome	Returns true if the option is a Some value.
Value	Gets the value of a Some option. A NullReferenceException is raised if the option is None.

Static Members

Member	Description
None	Creates an option value that is a None value.
Some	Creates an option value that is a Some value.

Union Cases

Case	Description
None	Specifies that there is no value.
Some of 'T	Contains the value, when there is a value.

Platforms

Windows 7, Windows Vista SP2, Windows XP SP3, Windows XP x64 SP2, Windows Server 2008 R2, Windows Server 2008 SP2, Windows Server 2003 SP2

Version Information

F# Runtime

Supported in: 2.0, 4.0

Silverlight

Supported in: 3

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