String Constructor (SByte*, Int32, Int32, Encoding)

Initializes a new instance of the String class to the value indicated by a specified pointer to an array of 8-bit signed integers, a starting character position within that array, a length, and an Encoding object.

This constructor is not CLS-compliant.  

Namespace: System
Assembly: mscorlib (in mscorlib.dll)

public String (
	sbyte* value,
	int startIndex,
	int length,
	Encoding enc
J# does not support APIs that consume or return unsafe types.
JScript does not support APIs that consume or return unsafe types.



A pointer to an array of 8-bit signed integers.


The starting position within value.


The number of characters within value to use.


An Encoding object that specifies how the array referenced by value is encoded. If enc is a null reference (Nothing in Visual Basic), ANSI encoding is assumed.

Exception typeCondition


value is a null reference (Nothing in Visual Basic).


startIndex or length is less than zero.


The address specified by value + startIndex is too large for the current platform; that is, the address calculation overflowed.


The length of the new string to initialize is too large to allocate.


The address specified by value + startIndex is less than 64K.


A new instance of String could not be initialized using value, assuming value is encoded as specified by enc.


value, startIndex, and length collectively specify an invalid address.

The value parameter is assumed to point to an array representing a string encoded as specified by enc.

If length is zero, the new instance is initialized to the empty string ("").

This constructor processes characters from value starting at startIndex and ending at (startIndex + length - 1).

If the specified range is outside of the memory allocated for the sequence of characters, the behavior of this constructor is system dependent. For example, such a situation might cause an access violation.

In C#, this constructor is defined only in the context of unsafe code.

The following simple code example demonstrates how you can create an instance of a UTF-8 String with this constructor.

    String utfeightstring = null;
    sbyte [] asciiChars = new sbyte[] { 0x51,0x52,0x53,0x54,0x54,0x56 };
    UTF8Encoding encoding = new UTF8Encoding(true, true);

    // Instruct the Garbage Collector not to move the memory
    fixed(sbyte* pAsciiChars = asciiChars)
        utfeightstring = new String(pAsciiChars,0,asciiChars.Length,encoding);
    Console.WriteLine("The UTF8 String is " + utfeightstring ); // prints "QRSTTV"

Windows 98, Windows 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0, 1.1, 1.0