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Core.DefaultValueAttribute Class (F#)

Adding this attribute to a field declaration means that the field is not initialized. During type checking a constraint is asserted that the field type supports null. If the Check value is false then the constraint is not asserted.

Namespace/Module Path: Microsoft.FSharp.Core

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

[<AttributeUsage(AttributeTargets.Field, AllowMultiple = false)>]
type DefaultValueAttribute =
  new DefaultValueAttribute : bool -> DefaultValueAttribute
  new DefaultValueAttribute : unit -> DefaultValueAttribute
  member this.Check :  bool

This attribute is intended to be used on explicit fields in classes and structures. It shouldn't be used on records. For more information, see Records (F#) and Explicit Fields: The val Keyword (F#).

The .NET Framework namespace System.ComponentModel defines an attribute that has the same name: DefaultValueAttribute. Therefore, you must fully qualify the F# attribute if you open the System.ComponentModel namespace.

You can also use the short form of the name, DefaultValue.




Creates an instance of the attribute




Indicates if a constraint is asserted that the field type supports 'null'

Windows 8, Windows 7, Windows Server 2012, Windows Server 2008 R2

F# Core Library Versions

Supported in: 2.0, 4.0, Portable

© 2015 Microsoft