String.ToLower Method (CultureInfo)
Returns a copy of this string converted to lowercase, using the casing rules of the specified culture.
Assembly: mscorlib (in mscorlib.dll)
culture is a null reference (Nothing in Visual Basic).
The casing rules of the culture specified by the culture parameter determine the way the case of the string is changed.
This method does not modify the value of the current instance. Instead, it returns a new string in which all characters in the current instance are converted to lowercase.
If you pass the method a CultureInfo object other than CultureInfo.InvariantCulture, the casing operation will take culture-specific rules into account. If you need the lowercase or uppercase version of an operating system identifier, such as a file name, named pipe, or registry key, use the ToLowerInvariant or ToUpperInvariant method. This produces the same result in every culture and performs more efficiently.
The following example converts two strings of uppercase characters to lowercase characters using the English-United States and Turkish-Turkey cultures, then compares the lowercase strings. The uppercase strings are identical except that for each occurrence of the Unicode LATIN CAPITAL LETTER I in one string, the other string contains LATIN CAPITAL LETTER I WITH DOT ABOVE.