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Char.ConvertToUtf32 Method (Char, Char)

Converts the value of a UTF-16 encoded surrogate pair into a Unicode code point.

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

public static int ConvertToUtf32(
	char highSurrogate,
	char lowSurrogate
)

Parameters

highSurrogate
Type: System.Char

A high surrogate code unit (that is, a code unit ranging from U+D800 through U+DBFF).

lowSurrogate
Type: System.Char

A low surrogate code unit (that is, a code unit ranging from U+DC00 through U+DFFF).

Return Value

Type: System.Int32
The 21-bit Unicode code point represented by the highSurrogate and lowSurrogate parameters.

ExceptionCondition
ArgumentOutOfRangeException

highSurrogate is not in the range U+D800 through U+DBFF, or lowSurrogate is not in the range U+DC00 through U+DFFF.

Use this method to convert a surrogate pair into a 21-bit Unicode code point. To convert UTF-16 data into UTF-32 data, use the System.Text.UTF32Encoding class.

Ordinarily, UTF-16 encoding represents a single Unicode character as a 16-bit code unit. However, it also supports surrogate pairs, which allow a single abstract character to be represented as two 16-bit code units. These two Char objects must have code units that range from U+D800 to U+DBFF for the first (high) surrogate and from U+DC00 to U+DFFF for the second (low) surrogate. Surrogate pairs are supported only by UTF-16 encoding. This method allows a character represented by a UTF-16 surrogate pair to be converted to a character using UTF-32 encoding.

The following code example demonstrates the ConvertToUtf32 and ConvertFromUtf32 methods.

// This example demonstrates the Char.ConvertFromUtf32() method 
//                           and Char.ConvertToUtf32() overloads. 
using System;

class Sample 
{
    public static void Main() 
    {
    int letterA = 0x0041;  //U+00041 = LATIN CAPITAL LETTER A 
    int music   = 0x1D161; //U+1D161 = MUSICAL SYMBOL SIXTEENTH NOTE 
    string s1;
    string comment   = "Create a UTF-16 encoded string from a code point.";
    string comment1b = "Create a code point from a UTF-16 encoded string.";
    string comment2b = "Create a code point from a surrogate pair at a certain position in a string.";
    string comment2c = "Create a code point from a high surrogate and a low surrogate code point.";

//  Convert code point U+0041 to UTF-16. The UTF-16 equivalent of  
//  U+0041 is a Char with hexadecimal value 0041.

    Console.WriteLine(comment);
    s1 = Char.ConvertFromUtf32(letterA);
    Console.Write("    1a) 0x{0:X} => ", letterA);
    Show(s1);
    Console.WriteLine();

//  Convert the lone UTF-16 character to a code point.

    Console.WriteLine(comment1b);
    letterA = Char.ConvertToUtf32(s1, 0);
    Console.Write("    1b) ");
    Show(s1);
    Console.WriteLine(" => 0x{0:X}", letterA);
    Console.WriteLine();

// ------------------------------------------------------------------- 

//  Convert the code point U+1D161 to UTF-16. The UTF-16 equivalent of  
//  U+1D161 is a surrogate pair with hexadecimal values D834 and DD61.

    Console.WriteLine(comment);
    s1 = Char.ConvertFromUtf32(music);
    Console.Write("    2a) 0x{0:X} => ", music);
    Show(s1);
    Console.WriteLine();

//  Convert the surrogate pair in the string at index position  
//  zero to a code point.

    Console.WriteLine(comment2b);
    music = Char.ConvertToUtf32(s1, 0);
    Console.Write("    2b) ");
    Show(s1);
    Console.WriteLine(" => 0x{0:X}", music);

//  Convert the high and low characters in the surrogate pair into a code point.

    Console.WriteLine(comment2c);
    music = Char.ConvertToUtf32(s1[0], s1[1]);
    Console.Write("    2c) ");
    Show(s1);
    Console.WriteLine(" => 0x{0:X}", music);
    }

    private static void Show(string s)
    {
    for (int x = 0; x < s.Length; x++)
        {
        Console.Write("0x{0:X}{1}", 
                       (int)s[x], 
                       ((x == s.Length-1)? String.Empty : ", "));
        }
    }
}
/*
This example produces the following results:

Create a UTF-16 encoded string from a code point.
    1a) 0x41 => 0x41
Create a code point from a UTF-16 encoded string.
    1b) 0x41 => 0x41

Create a UTF-16 encoded string from a code point.
    2a) 0x1D161 => 0xD834, 0xDD61
Create a code point from a surrogate pair at a certain position in a string.
    2b) 0xD834, 0xDD61 => 0x1D161
Create a code point from a high surrogate and a low surrogate code point.
    2c) 0xD834, 0xDD61 => 0x1D161

*/

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone Silverlight 8.1, Windows Phone Silverlight 8

Portable Class Library

Supported in: Portable Class Library
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