public static string Not(
	string s
)

Public Shared Function Not ( 
	s As String
) As String

Parameters

s

Type: SystemString
Search condition to be inverted.

Return Value

This method allows you to produce the inverted query you can then pass to Search(Boolean, String, String) method. You can combine this method with other methods like AnyOf(String) to build complex queries.

For instance, if s is SINCE 1-Feb-1994, the return value is NOT SINCE 1-Feb-1994.

Note
Many IMAP search conditions already have native inverse versions. For instance, KEYWORD has UNKEYWORD counterpart. However, there is no harm to use NOT with such conditions (i.e. NOT KEYWORD has exacty the same effect as UNKEYWORD).

Reference