How to mark classes, methods and properties as Obsolete / Deprecated in c# or vb.net

How can a class marked as Deprecated/Obsolete in c# or vb.NET?
You can mark a class, method or property by adding the Obsolete Attribute above the declaration.

Sample C#

[Obsolete("This class should not be used anymore!",true)]
public class MyObsoleteClass
{
	...
}

Sample VB.NET

<Obsolete("This class should not be used anymore!", True)> _
Public Class MyObsoleteClass
	...
End Class

Tip

The second parameter of the attribute indicates whether the obsolete Class/Method/Property element usage is considered as error or not.

for more information see the MSDN about ObsoleteAttribute Class