Changing Case of string in C#

String offers two convenient methods that enable us to change the case of letters within a string.these are ToUpper() and ToLower().

public string ToUpper()
public string ToLower()

ToUpper() uppercases all letters within the invoking string. ToLower() lowercases all letters within the invoking string.


C# added two another version of these methods that allow us to specify cultural settings: ToUpperInvariant() and ToLowerInvariant().

public string ToUpperInvariant()
public string ToLowerInvariant()

they work same as ToUpper() and ToLower() except they use the invariant cultural to perform transformations to upper or lower cases.


string str = “AuthorCode”;

string strUpper = str.ToUpper();
//value of strUpper=”AUTHORCODE”

string strlower = str.ToLower();
//value of strlower =”authorcode”