Seq.cast<'T> Function (F#)

Wraps a weakly typed System.Collections sequence as a typed sequence.

Namespace/Module Path: Microsoft.FSharp.Collections.Seq

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

// Signature:
Seq.cast : IEnumerable -> seq<'T>

// Usage:
Seq.cast source

Parameters

• source
  Type: IEnumerable

  The input sequence.

Exceptions

Exception	Condition
ArgumentNullException	Thrown when the input sequence is null.

Return Value

The result sequence.

Remarks

The use of this function usually requires a type annotation. An incorrect type annotation may result in runtime type errors. Individual IEnumerator values generated from the returned sequence should not be accessed concurrently.

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

Example

The following code demonstrates the use of Seq.cast to convert a weakly typed ArrayList, where the element type is just Object, into a sequence of int.

open System
let mutable arrayList1 = new System.Collections.ArrayList(10)
for i in 1 .. 10 do arrayList1.Add(10) |> ignore
let seqCast : seq<int> = Seq.cast arrayList1

Platforms

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

Version Information

F# Core Library Versions

Supported in: 2.0, 4.0, Portable

See Also

Reference

Collections.Seq Module (F#)

Microsoft.FSharp.Collections Namespace (F#)