Char.ConvertFromUtf32(Int32) 方法
定義
重要
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將指定之 Unicode 字碼指標轉換成 UTF-16 編碼的字串。
public:
static System::String ^ ConvertFromUtf32(int utf32);public static string ConvertFromUtf32 (int utf32);static member ConvertFromUtf32 : int -> stringPublic Shared Function ConvertFromUtf32 (utf32 As Integer) As String參數
- utf32
- Int32
21 位元 Unicode 字碼指標。
傳回
由一個 Char 物件或 Char 物件的 Surrogate 字組所組成的字串，這些物件相當於 utf32 參數所指定的字碼指標。
例外狀況
utf32 不是範圍從 U+0 到 U+10FFFF，且排除範圍從 U+D800 到 U+DFFF 之 Surrogate 字組的有效 21 位元 Unicode 字碼指標。
範例
下列程式碼範例示範 ConvertToUtf32 和 ConvertFromUtf32 方法。
// 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
'
備註
使用這個方法，先將 21 位 Unicode 字碼點轉換成 UTF-16 編碼字串，然後再使用 和 IsHighSurrogate(Char) 等 IsLowSurrogate(Char) 方法測試字串。
基本多語系平面以外的有效代碼點 (BMP) 一律會產生有效的代理字組。 不過，BMP 內的有效字碼點可能不會根據 Unicode 標準產生有效的結果，因為轉換中不會使用任何語言處理。 基於這個理由，請使用 System.Text.UTF32Encoding 類別將大量 UTF-32 資料轉換成大量 UTF-16 資料。
