C# 0 The Complete Reference

StringBuilder

, which is in 

the

System.Text

 namespace. For most purposes, however, you will want to use 

string

, not 

StringBuilder

.

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CHAPTER

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The String Class

String

 is defined in the 

System

 namespace. It implements the 

IComparable

,

IComparable

,

ICloneable

,

IConvertible

,

IEnumerable

,

IEnumerable

,

and

IEquatable

 interfaces. 

String

 is a sealed class, which means that it cannot be 

inherited.

String

 provides string-handling functionality for C#. It underlies C#’s built-in 

string

 type and is part of the .NET Framework. The next few sections examine 

String

in detail.

The String Constructors

The

String

 class defines several constructors that allow you to construct a string in a variety 

of ways. To create a string from a character array, use one of these constructors:

public String(char[ ] 

chrs

)

public String(char[ ] 

chrs

, int 

start

, int 

count

)

The first form constructs a string that contains the characters in 

chrs.

 The second form uses 

count

 characters from 

chrs,

 beginning at the index specified by 

start.

You can create a string that contains a specific character repeated a number of times 

using this constructor:

public String(char 

ch

, int 

count

)

Here, 

ch

 specifies the character that will be repeated 

count

 times.

You can construct a string given a pointer to a character array using one of these 

constructors:

public String(char* 

chrs

)

public String(char* 

chrs

, int 

start

, int 

count

)

The first form constructs a string that contains the characters pointed to by 

chrs.

 It is assumed 

that

chrs

 points to a null-terminated array, which is used in its entirety. The second form uses 

count

 characters from the array pointed to by 

chrs,

 beginning at the index specified by 

start.

Because they use pointers, these constructors can be used only in unsafe code.

You can construct a string given a pointer to an array of bytes using one of these 

constructors:

public String(sbyte* 

chrs

)

public String(sbyte* 

chrs

, int 

start

, int 

count

)

public String(sbyte* 

chrs

, int 

start

, int 

count

, Encoding 

en

)

The first form constructs a string that contains the bytes pointed to by 

chrs.

 It is assumed 

that

chrs

 points to a null-terminated array, which is used in its entirety. The second form 

uses

count

 characters from the array pointed to by 

chrs,

 beginning at the index specified by 

start.

 The third form lets you specify how the bytes are encoded. The default encoding is 

ASCIIEncoding

. The 

Encoding

 class is in the 

System.Text

 namespace. Because they use 

pointers, these constructors can be used only in unsafe code.

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