Char.ConvertFromUtf32(Int32) Metoda

Reference

Definice

Obor názvů:: System

Sestavení:: System.Runtime.dll

Sestavení:: netstandard.dll

Sestavení:: mscorlib.dll

Důležité

Některé informace platí pro předběžně vydaný produkt, který se může zásadně změnit, než ho výrobce nebo autor vydá. Microsoft neposkytuje žádné záruky, výslovné ani předpokládané, týkající se zde uváděných informací.

Převede zadaný bod kódu Unicode na řetězec kódovaný v kódování UTF-16.

public:
 static System::String ^ ConvertFromUtf32(int utf32);

public static string ConvertFromUtf32 (int utf32);

static member ConvertFromUtf32 : int -> string

Public Shared Function ConvertFromUtf32 (utf32 As Integer) As String

Parametry

utf32: Int32

16bitový bod kódu Unicode.

Návraty

String

Řetězec skládající se z jednoho Char objektu nebo náhradního páru Char objektů, které odpovídají bodu kódu určenému utf32 parametrem.

Výjimky

ArgumentOutOfRangeException

utf32 není platným koncovým bodem v kódování Unicode v rozsahu od U + 0 do U + 10FFFF, s výjimkou rozsahu náhradního páru od U + D800 až U + DFFF.

Příklady

Následující příklad kódu ukazuje ConvertToUtf32 ConvertFromUtf32 metody a.

// This example demonstrates the Char.ConvertFromUtf32() method
//                           and Char.ConvertToUtf32() overloads.
using namespace System;
void Show( String^ s )
{
//   Console::Write( "0x{0:X}, 0x{1:X}", (int)s->get_Chars( 0 ), (int)s->get_Chars( 1 ) );
   Console::Write( "0x{0:X}, 0x{1:X}", (int)s[ 0 ], (int)s[ 1 ] );
}

int main()
{
   int music = 0x1D161; //U+1D161 = MUSICAL SYMBOL SIXTEENTH NOTE

   String^ s1;
   String^ comment1a = "Create a UTF-16 encoded string from a code point.";
   String^ comment1b = "Create a code point from a surrogate pair at a certain position in a string.";
   String^ comment1c = "Create a code point from a high surrogate and a low surrogate code point.";
   
   // -------------------------------------------------------------------
   //  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( comment1a );
   s1 = Char::ConvertFromUtf32( music );
   Console::Write( "    1a) 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( comment1b );
   music = Char::ConvertToUtf32( s1, 0 );
   Console::Write( "    1b) " );
   Show( s1 );
   Console::WriteLine( " => 0x{0:X}", music );
   
   //  Convert the high and low characters in the surrogate pair into a code point.
   Console::WriteLine( comment1c );
   music = Char::ConvertToUtf32( s1[ 0 ], s1[ 1 ] );
   Console::Write( "    1c) " );
   Show( s1 );
   Console::WriteLine( " => 0x{0:X}", music );
}

/*
This example produces the following results:

Create a UTF-16 encoded string from a code point.
    1a) 0x1D161 => 0xD834, 0xDD61
Create a code point from a surrogate pair at a certain position in a string.
    1b) 0xD834, 0xDD61 => 0x1D161
Create a code point from a high surrogate and a low surrogate code point.
    1c) 0xD834, 0xDD61 => 0x1D161

*/

// 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

*/

open System

let show (s: string) =
    for x = 0 to s.Length - 1 do
        printf $"""0x{int s[x]:X}{if x = s.Length - 1 then String.Empty else ", "}"""                    

[<EntryPoint>]
let main _ =
    let letterA = 0x0041  //U+00041 = LATIN CAPITAL LETTER A
    let music   = 0x1D161 //U+1D161 = MUSICAL SYMBOL SIXTEENTH NOTE
    let comment   = "Create a UTF-16 encoded string from a code point."
    let comment1b = "Create a code point from a UTF-16 encoded string."
    let comment2b = "Create a code point from a surrogate pair at a certain position in a string."
    let 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.

    printfn $"{comment}"
    let s1 = Char.ConvertFromUtf32 letterA
    printf $"    1a) 0x{letterA:X} => "
    show s1
    printfn ""

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

    printfn $"{comment1b}"
    let letterA = Char.ConvertToUtf32(s1, 0)
    printf "    1b) "
    show s1
    printfn $" => 0x{letterA:X}"
    printfn ""

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

//  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.

    printfn $"{comment}"
    let s1 = Char.ConvertFromUtf32 music
    printf $"    2a) 0x{music:X} => "
    show s1
    printfn ""

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

    printfn $"{comment2b}" 
    let music = Char.ConvertToUtf32(s1, 0)
    printf "    2b) "
    show s1
    printfn $" => 0x{music:X}"

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

    printfn $"{comment2c}"
    let music = Char.ConvertToUtf32(s1[0], s1[1])
    printf "    2c) "
    show s1
    printfn $" => 0x{music:X}"

    0

// 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

Class Sample
   Public Shared Sub Main()
      Dim letterA As Integer = &H41    'U+00041 = LATIN CAPITAL LETTER A
      Dim music As Integer   = &H1D161 'U+1D161 = MUSICAL SYMBOL SIXTEENTH NOTE
      Dim s1 As String
      Dim comment   As String = "Create a UTF-16 encoded string from a code point."
      Dim comment1b As String = "Create a code point from a UTF-16 encoded string."
      Dim comment2b As String = "Create a code point from a surrogate pair at a certain position in a string."
      Dim comment2c As String = "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.Chars(0), s1.Chars(1))
      Console.Write("    2c) ")
      Show(s1)
      Console.WriteLine(" => 0x{0:X}", music)
   End Sub
   
   Private Shared Sub Show(s As String)
      Dim x As Integer
      If s.Length = 0 Then Exit Sub
      For x = 0 To s.Length - 1
         Console.Write("0x{0:X}{1}", _
                        AscW(s.Chars(x)), _
                        IIf(x = s.Length - 1, [String].Empty, ", "))
      Next 
   End Sub 
End Class 
'
'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
'

Poznámky

Tuto metodu použijte, chcete-li převést 16bitový bod kódu Unicode na řetězec kódovaný v kódování UTF-16 před testováním řetězce s metodami, jako jsou IsLowSurrogate(Char) a IsHighSurrogate(Char) .

Platný bod kódu mimo základní vícejazyčné rovině (BMP) vždy vytvoří platný náhradní pár. Platný bod kódu v rámci BMP ale nemusí vracet platný výsledek podle standardu Unicode, protože v převodu se nepoužívá žádné jazykové zpracování. Z tohoto důvodu použijte System.Text.UTF32Encoding třídu pro převod hromadných dat UTF-32 do hromadných dat UTF-16.

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