C# in a Nutshell, Second Edition

Name

String

Synopsis

This class consists of an immutable array of Char characters and built-in helper functions. Methods that appear to modify a string, such as Concat( ), actually create and return a new String object. To modify a string directly, use the System.Text.StringBuilder class. This can enhance performance in some routines that make intensive use of string-manipulation operations. In C#, String is aliased as string.

A string is slightly unusual because it is a reference type that behaves like a value type for comparison and assignment operations. Two String objects with the same content but different locations in memory return true when tested for equality. Also, assigning one String to another clones the string itself, rather than just duplicating the reference.

On the other hand, a String is a fully featured object with a Length property and a wide variety of methods for the following: padding or trimming specified characters on either side, converting case, performing inline substitutions (with Replace( )), and dividing a string into an array of strings (with Split( )). There’s also a default indexer that lets you retrieve a single character. Note that strings are zero-based, and the first character is string[0].

You can create a string made up of a single repeated character by using an alternate constructor and supplying a char and the number of repetitions.

public sealed class String : IComparable, ICloneable, IConvertible, IEnumerable {
// Public Constructors public ...