Marking a method as Obsolete/Deprecated in C#

The following C# code shows you how to use the Obsolete attribute to mark members and or types as obsolete. When a method has the Obsolete attribute, the C# compiler issues a warning if it is called. This helps keep programs correct. This makes it easier to transition from old methods.

[Obsolete("Use Dispose() instead")]

public void Close()

{

  Dispose();

}

Adding a true value as second parameter, you can also cause the compilation to fail  instead of warning if the method is called from somewhere in code.

[Obsolete("Use Dispose() instead"), true]

public void Close()

{

  Dispose();

}