ReadOnly Method (IList)
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ArrayList.ReadOnly Method (IList)

Returns a read-only IList wrapper.

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

public static IList ReadOnly(
	IList list


Type: System.Collections.IList
The IList to wrap.

Return Value

Type: System.Collections.IList
A read-only IList wrapper around list.


list is null.

To prevent any modifications to list, expose list only through this wrapper.

A collection that is read-only is simply a collection with a wrapper that prevents modifying the collection. If changes are made to the underlying collection, the read-only collection reflects those changes.

This method is an O(1) operation.

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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