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IdnMapping.GetAscii Method (String, Int32)

Note: This method is new in the .NET Framework version 2.0.

Encodes a substring of one or more domain name labels that consist of Unicode characters to a string of Unicode characters in the US-ASCII character range.

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

public string GetAscii (
	string unicode,
	int index
public String GetAscii (
	String unicode, 
	int index
public function GetAscii (
	unicode : String, 
	index : int
) : String



An input string to convert, which consists of one or more domain name labels delimited with label separators.


A zero-based offset into unicode that specifies the start of the substring. The conversion operation continues to the end of unicode.

Return Value

The equivalent of the substring specified by the unicode and index parameters, consisting of displayable Unicode characters in the US-ASCII character range (U+0020 to U+007E) and formatted according to the Internationalizing Domain Names in Applications (IDNA) standard.

Exception typeCondition


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


index or count is less than zero.


index is greater than the length of unicode.


unicode is invalid based on the AllowUnassigned and UseStd3AsciiRules properties, and the IDNA standard.


A label contains one or more of the Unicode control characters from U+0001 through U+001F, or U+007F.

For more information about domain names, labels, and label separators, see the remarks for the IdnMapping.GetAscii(String,Int32,Int32) method.

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