Changing the case of characters within a String C# with Example
The System.String class supports a number of methods to convert between uppercase and lowercase characters
in a string.
System.String.ToLowerInvariant is used to return a String object converted to lowercase.
System.String.ToUpperInvariant is used to return a String object converted to uppercase.
Note: The reason to use the invariant versions of these methods is to prevent producing unexpected culture-
speciﬁc letters. This is explained here in detail.
string s = "My String";
s = s.ToLowerInvariant(); // "my string"
s = s.ToUpperInvariant(); // "MY STRING"
Note that you can choose to specify a speciﬁc Culture when converting to lowercase and uppercase by using the
String.ToLower(CultureInfo) and String.ToUpper(CultureInfo) methods accordingly.