.NET Framework Class Library
ObsoleteAttribute Class
Marks the program elements that are no longer in use. This class cannot be inherited.
Inheritance Hierarchy
System.Object
System.Attribute
System.ObsoleteAttribute
Namespace: System
Assembly: mscorlib (in mscorlib.dll)
Syntax
Visual Basic
<SerializableAttribute> _ <AttributeUsageAttribute(AttributeTargets.Class Or AttributeTargets.Struct Or AttributeTargets.Enum Or AttributeTargets.Constructor Or AttributeTargets.Method Or AttributeTargets.Property Or AttributeTargets.Field Or AttributeTargets.Event Or AttributeTargets.Interface Or AttributeTargets.Delegate, Inherited := False)> _ <ComVisibleAttribute(True)> _ Public NotInheritable Class ObsoleteAttribute _ Inherits Attribute
C#
[SerializableAttribute] [AttributeUsageAttribute(AttributeTargets.Class|AttributeTargets.Struct|AttributeTargets.Enum|AttributeTargets.Constructor|AttributeTargets.Method|AttributeTargets.Property|AttributeTargets.Field|AttributeTargets.Event|AttributeTargets.Interface|AttributeTargets.Delegate, Inherited = false)] [ComVisibleAttribute(true)] public sealed class ObsoleteAttribute : Attribute
Visual C++
[SerializableAttribute] [AttributeUsageAttribute(AttributeTargets::Class|AttributeTargets::Struct|AttributeTargets::Enum|AttributeTargets::Constructor|AttributeTargets::Method|AttributeTargets::Property|AttributeTargets::Field|AttributeTargets::Event|AttributeTargets::Interface|AttributeTargets::Delegate, Inherited = false)] [ComVisibleAttribute(true)] public ref class ObsoleteAttribute sealed : public Attribute
F#
[<Sealed>] [<SerializableAttribute>] [<AttributeUsageAttribute(AttributeTargets.Class|AttributeTargets.Struct|AttributeTargets.Enum|AttributeTargets.Constructor|AttributeTargets.Method|AttributeTargets.Property|AttributeTargets.Field|AttributeTargets.Event|AttributeTargets.Interface|AttributeTargets.Delegate, Inherited = false)>] [<ComVisibleAttribute(true)>] type ObsoleteAttribute = class inherit Attribute end
The ObsoleteAttribute type exposes the following members.
Constructors
| Name | Description | |
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ObsoleteAttribute() | Initializes a new instance of the ObsoleteAttribute class with default properties. |
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ObsoleteAttribute(String) | Initializes a new instance of the ObsoleteAttribute class with a specified workaround message. |
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ObsoleteAttribute(String, Boolean) | Initializes a new instance of the ObsoleteAttribute class with a workaround message and a Boolean value indicating whether the obsolete element usage is considered an error. |
Properties
| Name | Description | |
|---|---|---|
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IsError | Gets a Boolean value indicating whether the compiler will treat usage of the obsolete program element as an error. |
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Message | Gets the workaround message, including a description of the alternative program elements. |
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TypeId | When implemented in a derived class, gets a unique identifier for this Attribute. (Inherited from Attribute.) |
Methods
| Name | Description | |
|---|---|---|
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Equals | Infrastructure. Returns a value that indicates whether this instance is equal to a specified object. (Inherited from Attribute.) |
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Finalize | Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.) |
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GetHashCode | Returns the hash code for this instance. (Inherited from Attribute.) |
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GetType | Gets the Type of the current instance. (Inherited from Object.) |
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IsDefaultAttribute | When overridden in a derived class, indicates whether the value of this instance is the default value for the derived class. (Inherited from Attribute.) |
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Match | When overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute.) |
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MemberwiseClone | Creates a shallow copy of the current Object. (Inherited from Object.) |
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ToString | Returns a string that represents the current object. (Inherited from Object.) |
Explicit Interface Implementations
| Name | Description | |
|---|---|---|
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_Attribute.GetIDsOfNames | Maps a set of names to a corresponding set of dispatch identifiers. (Inherited from Attribute.) |
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_Attribute.GetTypeInfo | Retrieves the type information for an object, which can be used to get the type information for an interface. (Inherited from Attribute.) |
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_Attribute.GetTypeInfoCount | Retrieves the number of type information interfaces that an object provides (either 0 or 1). (Inherited from Attribute.) |
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_Attribute.Invoke | Provides access to properties and methods exposed by an object. (Inherited from Attribute.) |
Remarks
ObsoleteAttribute is applicable to all program elements except assemblies, modules, parameters or return values. Marking an element as obsolete informs the users that the element will be removed in future versions of the product.
For more information about using attributes, see Extending Metadata Using Attributes.
Examples
The following example defines a class that contains a method marked with the ObsoleteAttribute. Any code that attempts to call the method will cause the compiler to issue a warning.
Visual Basic
Module Module1 Sub Main() ' The line below causes the compiler to issue a warning: ' 'App.SomeDeprecatedMethod()' is obsolete: 'Do not call this method.' SomeDeprecatedMethod() End Sub ' The method below is marked with the ObsoleteAttribute. ' Any code that attempts to call this method will get a warning. <Obsolete("Do not call this method.")> Private Sub SomeDeprecatedMethod() End Sub End Module
C#
using System; public sealed class App { static void Main() { // The line below causes the compiler to issue a warning: // 'App.SomeDeprecatedMethod()' is obsolete: 'Do not call this method.' SomeDeprecatedMethod(); } // The method below is marked with the ObsoleteAttribute. // Any code that attempts to call this method will get a warning. [Obsolete("Do not call this method.")] private static void SomeDeprecatedMethod() { } }
Visual C++
using namespace System; // The method below is marked with the ObsoleteAttribute. // Any code that attempts to call this method will get a warning. [Obsolete("Do not call this method.")] void SomeDeprecatedMethod() { } int main() { // The line below causes the compiler to issue a warning: // 'SomeDeprecatedMethod()': marked as obsolete // Message: 'Do not call this method.' SomeDeprecatedMethod(); }
Version Information
.NET Framework
Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0.NET Framework Client Profile
Supported in: 4, 3.5 SP1Portable Class Library
Supported in: Portable Class LibraryPlatforms
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.
Thread Safety
Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.See Also
Reference
Other Resources
Community Content
Mike Edenfield
ObsoleteAttribute and extension methods
The ObsoleteAttribute applied at the class level will not cause any extension methods in that class to be flagged as obsolete. The attribute needs to be applied at the method level to be detected. The following code will compile without warning:
$0$0
$0
[Obsolete("old")]
public static class FooExtensions
{
public static bool Bigger ( this String s, int size )
{
return s.Length > size;
}
}
public class Foo
{
public void Test ()
{
string s = "This is a test.";
Console.WriteLine("{0} is {1}bigger than {2} characters.", s, s.Bigger(5) ? "" : "not ", 5);
}
}
$0
$0$0
Charles Lambert
obsolete calls to obsolete stuff does not throw compiler warning
Code marked with the ObsoleteAttribute will not generate a compiler warning when that code is calling code that is also marked with the ObsoleteAttribute.
For example Foo (see Class1 below) does not generate a compiler warning even though Bar is marked with the ObsoleteAttribute. If you remove the ObsoleteAttribute from Foo, then a compiler warning is generated. I noticed when adding the ObsoleteAttribute to Foo( the only code change) that the compiler warning still existed until I did a rebuild. If you have non-obsolete code calling obsolete code then the warning is valid. I would not recomend using the #pragma warning directive to disable this warning
public class Class1 {
[Obsolete("don't use me either")]
public void Foo() {
Console.WriteLine("Old code calling old code.");
Bar();
}
[Obsolete("don't use me")]
public void Bar() {
Console.WriteLine("Old code");
}
}
For example Foo (see Class1 below) does not generate a compiler warning even though Bar is marked with the ObsoleteAttribute. If you remove the ObsoleteAttribute from Foo, then a compiler warning is generated. I noticed when adding the ObsoleteAttribute to Foo( the only code change) that the compiler warning still existed until I did a rebuild. If you have non-obsolete code calling obsolete code then the warning is valid. I would not recomend using the #pragma warning directive to disable this warning
public class Class1 {
[Obsolete("don't use me either")]
public void Foo() {
Console.WriteLine("Old code calling old code.");
Bar();
}
[Obsolete("don't use me")]
public void Bar() {
Console.WriteLine("Old code");
}
}