CharIsSurrogatePair Method
 

Indicates whether the two specified Char objects form a surrogate pair.

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

Syntax
public static bool IsSurrogatePair(
	char highSurrogate,
	char lowSurrogate
)
public:
static bool IsSurrogatePair(
	wchar_t highSurrogate,
	wchar_t lowSurrogate
)
static member IsSurrogatePair : 
        highSurrogate:char *
        lowSurrogate:char -> bool
Public Shared Function IsSurrogatePair (
	highSurrogate As Char,
	lowSurrogate As Char
) As Boolean

Parameters

highSurrogate
Type:

The character to evaluate as the high surrogate of a surrogate pair.

lowSurrogate
Type:

The character to evaluate as the low surrogate of a surrogate pair.

Return Value

Type:

true if the numeric value of the highSurrogate parameter ranges from U+D800 through U+DBFF, and the numeric value of the lowSurrogate parameter ranges from U+DC00 through U+DFFF; otherwise, false.

Remarks

Ordinarily, a single character is represented by a single 16-bit Unicode code unit. UTF-16 encoding also supports surrogate pairs, which allow a single abstract character to be represented by two 16-bit code units. The first code unit, whose value can range from U+D800 to U+DBFF, is the high surrogate. The second code unit, whose value can range from U+DC00 to U+DFFF, is the low surrogate. Individual surrogate code points have no interpretation of their own. For more information about surrogates and the Unicode Standard, see the Unicode home page.

Examples

The following code example demonstrates the IsHighSurrogate, IsLowSurrogate, and IsSurrogatePair methods.

// This example demonstrates the Char.IsLowSurrogate() method
//                                    IsHighSurrogate() method
//                                    IsSurrogatePair() method
using System;

class Sample 
{
    public static void Main() 
    {
    char cHigh = '\uD800';
    char cLow  = '\uDC00';
    string s1  = new String(new char[] {'a', '\uD800', '\uDC00', 'z'});
    string divider = String.Concat( Environment.NewLine, new String('-', 70), 
                                    Environment.NewLine);

    Console.WriteLine();
    Console.WriteLine("Hexadecimal code point of the character, cHigh: {0:X4}", (int)cHigh);
    Console.WriteLine("Hexadecimal code point of the character, cLow:  {0:X4}", (int)cLow);
    Console.WriteLine();
    Console.WriteLine("Characters in string, s1: 'a', high surrogate, low surrogate, 'z'");
    Console.WriteLine("Hexadecimal code points of the characters in string, s1: ");
    for(int i = 0; i < s1.Length; i++)
        {
        Console.WriteLine("s1[{0}] = {1:X4} ", i, (int)s1[i]);
        }
    Console.WriteLine(divider);

    Console.WriteLine("Is each of the following characters a high surrogate?");
    Console.WriteLine("A1) cLow?  - {0}", Char.IsHighSurrogate(cLow));
    Console.WriteLine("A2) cHigh? - {0}", Char.IsHighSurrogate(cHigh));
    Console.WriteLine("A3) s1[0]? - {0}", Char.IsHighSurrogate(s1, 0));
    Console.WriteLine("A4) s1[1]? - {0}", Char.IsHighSurrogate(s1, 1));
    Console.WriteLine(divider);

    Console.WriteLine("Is each of the following characters a low surrogate?");
    Console.WriteLine("B1) cLow?  - {0}", Char.IsLowSurrogate(cLow));
    Console.WriteLine("B2) cHigh? - {0}", Char.IsLowSurrogate(cHigh));
    Console.WriteLine("B3) s1[0]? - {0}", Char.IsLowSurrogate(s1, 0));
    Console.WriteLine("B4) s1[2]? - {0}", Char.IsLowSurrogate(s1, 2));
    Console.WriteLine(divider);

    Console.WriteLine("Is each of the following pairs of characters a surrogate pair?");
    Console.WriteLine("C1) cHigh and cLow?  - {0}", Char.IsSurrogatePair(cHigh, cLow));
    Console.WriteLine("C2) s1[0] and s1[1]? - {0}", Char.IsSurrogatePair(s1, 0));
    Console.WriteLine("C3) s1[1] and s1[2]? - {0}", Char.IsSurrogatePair(s1, 1));
    Console.WriteLine("C4) s1[2] and s1[3]? - {0}", Char.IsSurrogatePair(s1, 2));
    Console.WriteLine(divider);
    }
}
/*
This example produces the following results:

Hexadecimal code point of the character, cHigh: D800
Hexadecimal code point of the character, cLow:  DC00

Characters in string, s1: 'a', high surrogate, low surrogate, 'z'
Hexadecimal code points of the characters in string, s1:
s1[0] = 0061
s1[1] = D800
s1[2] = DC00
s1[3] = 007A

----------------------------------------------------------------------

Is each of the following characters a high surrogate?
A1) cLow?  - False
A2) cHigh? - True
A3) s1[0]? - False
A4) s1[1]? - True

----------------------------------------------------------------------

Is each of the following characters a low surrogate?
B1) cLow?  - True
B2) cHigh? - False
B3) s1[0]? - False
B4) s1[2]? - True

----------------------------------------------------------------------

Is each of the following pairs of characters a surrogate pair?
C1) cHigh and cLow?  - True
C2) s1[0] and s1[1]? - False
C3) s1[1] and s1[2]? - True
C4) s1[2] and s1[3]? - False

----------------------------------------------------------------------

*/
' This example demonstrates the Char.IsLowSurrogate() method
'                                    IsHighSurrogate() method
'                                    IsSurrogatePair() method
Imports System
Imports Microsoft.VisualBasic

Class Sample
   Public Shared Sub Main()
      Dim cHigh As Char = ChrW(&HD800)
      Dim cLow  As Char = ChrW(&HDC00)
      Dim s1 = New [String](New Char() {"a"c, ChrW(&HD800), ChrW(&HDC00), "z"c})
      Dim divider As String = [String].Concat(Environment.NewLine, _
                                              New [String]("-"c, 70), _
                                              Environment.NewLine)

      Console.WriteLine()
      Console.WriteLine("Hexadecimal code point of the character, cHigh: {0:X4}", AscW(cHigh))
      Console.WriteLine("Hexadecimal code point of the character, cLow:  {0:X4}", AscW(cLow))
      Console.WriteLine()
      Console.WriteLine("Characters in string, s1: 'a', high surrogate, low surrogate, 'z'")
      Console.WriteLine("Hexadecimal code points of the characters in string, s1: ")
      Dim i As Integer
      For i = 0 To s1.Length - 1
         Console.WriteLine("s1({0}) = {1:X4} ", i, AscW(s1.Chars(i)))
      Next i
      Console.WriteLine(divider)

      Console.WriteLine("Is each of the following characters a high surrogate?")
      Console.WriteLine("A1) cLow?  - {0}", [Char].IsHighSurrogate(cLow))
      Console.WriteLine("A2) cHigh? - {0}", [Char].IsHighSurrogate(cHigh))
      Console.WriteLine("A3) s1(0)? - {0}", [Char].IsHighSurrogate(s1, 0))
      Console.WriteLine("A4) s1(1)? - {0}", [Char].IsHighSurrogate(s1, 1))
      Console.WriteLine(divider)

      Console.WriteLine("Is each of the following characters a low surrogate?")
      Console.WriteLine("B1) cLow?  - {0}", [Char].IsLowSurrogate(cLow))
      Console.WriteLine("B2) cHigh? - {0}", [Char].IsLowSurrogate(cHigh))
      Console.WriteLine("B3) s1(0)? - {0}", [Char].IsLowSurrogate(s1, 0))
      Console.WriteLine("B4) s1(2)? - {0}", [Char].IsLowSurrogate(s1, 2))
      Console.WriteLine(divider)

      Console.WriteLine("Is each of the following pairs of characters a surrogate pair?")
      Console.WriteLine("C1) cHigh and cLow?  - {0}", [Char].IsSurrogatePair(cHigh, cLow))
      Console.WriteLine("C2) s1(0) and s1(1)? - {0}", [Char].IsSurrogatePair(s1, 0))
      Console.WriteLine("C3) s1(1) and s1(2)? - {0}", [Char].IsSurrogatePair(s1, 1))
      Console.WriteLine("C4) s1(2) and s1(3)? - {0}", [Char].IsSurrogatePair(s1, 2))
      Console.WriteLine(divider)
   End Sub 'Main
End Class 'Sample
'
'This example produces the following results:
'
'Hexadecimal code point of the character, cHigh: D800
'Hexadecimal code point of the character, cLow:  DC00
'
'Characters in string, s1: 'a', high surrogate, low surrogate, 'z'
'Hexadecimal code points of the characters in string, s1:
's1(0) = 0061
's1(1) = D800
's1(2) = DC00
's1(3) = 007A
'
'----------------------------------------------------------------------
'
'Is each of the following characters a high surrogate?
'A1) cLow?  - False
'A2) cHigh? - True
'A3) s1(0)? - False
'A4) s1(1)? - True
'
'----------------------------------------------------------------------
'
'Is each of the following characters a low surrogate?
'B1) cLow?  - True
'B2) cHigh? - False
'B3) s1(0)? - False
'B4) s1(2)? - True
'
'----------------------------------------------------------------------
'
'Is each of the following pairs of characters a surrogate pair?
'C1) cHigh and cLow?  - True
'C2) s1(0) and s1(1)? - False
'C3) s1(1) and s1(2)? - True
'C4) s1(2) and s1(3)? - False
'
'----------------------------------------------------------------------
'
// This example demonstrates the Char.IsLowSurrogate() method
//                                    IsHighSurrogate() method
//                                    IsSurrogatePair() method
using namespace System;
int main()
{
   Char cHigh = L'\xD800';
   Char cLow = L'\xDC00';
   array<Char>^temp0 = {L'a',L'\xD800',L'\xDC00',L'z'};
   String^ s1 = gcnew String( temp0 );
   String^ divider = String::Concat( Environment::NewLine, gcnew String( '-',70 ), Environment::NewLine );
   Console::WriteLine();
   Console::WriteLine( "Hexadecimal code point of the character, cHigh: {0:X4}", (int)cHigh );
   Console::WriteLine( "Hexadecimal code point of the character, cLow:  {0:X4}", (int)cLow );
   Console::WriteLine();
   Console::WriteLine( "Characters in string, s1: 'a', high surrogate, low surrogate, 'z'" );
   Console::WriteLine( "Hexadecimal code points of the characters in string, s1: " );
   for ( int i = 0; i < s1->Length; i++ )
   {
      Console::WriteLine( "s1[{0}] = {1:X4} ", i, (int)s1[ i ] );
   }
   Console::WriteLine( divider );
   Console::WriteLine( "Is each of the following characters a high surrogate?" );
   Console::WriteLine( "A1) cLow?  - {0}", Char::IsHighSurrogate( cLow ) );
   Console::WriteLine( "A2) cHigh? - {0}", Char::IsHighSurrogate( cHigh ) );
   Console::WriteLine( "A3) s1[0]? - {0}", Char::IsHighSurrogate( s1, 0 ) );
   Console::WriteLine( "A4) s1[1]? - {0}", Char::IsHighSurrogate( s1, 1 ) );
   Console::WriteLine( divider );
   Console::WriteLine( "Is each of the following characters a low surrogate?" );
   Console::WriteLine( "B1) cLow?  - {0}", Char::IsLowSurrogate( cLow ) );
   Console::WriteLine( "B2) cHigh? - {0}", Char::IsLowSurrogate( cHigh ) );
   Console::WriteLine( "B3) s1[0]? - {0}", Char::IsLowSurrogate( s1, 0 ) );
   Console::WriteLine( "B4) s1[2]? - {0}", Char::IsLowSurrogate( s1, 2 ) );
   Console::WriteLine( divider );
   Console::WriteLine( "Is each of the following pairs of characters a surrogate pair?" );
   Console::WriteLine( "C1) cHigh and cLow?  - {0}", Char::IsSurrogatePair( cHigh, cLow ) );
   Console::WriteLine( "C2) s1[0] and s1[1]? - {0}", Char::IsSurrogatePair( s1, 0 ) );
   Console::WriteLine( "C3) s1[1] and s1[2]? - {0}", Char::IsSurrogatePair( s1, 1 ) );
   Console::WriteLine( "C4) s1[2] and s1[3]? - {0}", Char::IsSurrogatePair( s1, 2 ) );
   Console::WriteLine( divider );
}

/*
This example produces the following results:

Hexadecimal code point of the character, cHigh: D800
Hexadecimal code point of the character, cLow:  DC00

Characters in string, s1: 'a', high surrogate, low surrogate, 'z'
Hexadecimal code points of the characters in string, s1:
s1[0] = 0061
s1[1] = D800
s1[2] = DC00
s1[3] = 007A

----------------------------------------------------------------------

Is each of the following characters a high surrogate?
A1) cLow?  - False
A2) cHigh? - True
A3) s1[0]? - False
A4) s1[1]? - True

----------------------------------------------------------------------

Is each of the following characters a low surrogate?
B1) cLow?  - True
B2) cHigh? - False
B3) s1[0]? - False
B4) s1[2]? - True

----------------------------------------------------------------------

Is each of the following pairs of characters a surrogate pair?
C1) cHigh and cLow?  - True
C2) s1[0] and s1[1]? - False
C3) s1[1] and s1[2]? - True
C4) s1[2] and s1[3]? - False

----------------------------------------------------------------------

*/
Version Information
Universal Windows Platform
Available since 8
.NET Framework
Available since 2.0
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
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