Char.IsSurrogate Method

Definition

Namespace:

System

Assembly:

System.Runtime.dll

Indicates whether a character has a surrogate code unit.

Overloads

IsSurrogate(String, Int32)	Indicates whether the character at the specified position in a specified string has a surrogate code unit.
IsSurrogate(Char)	Indicates whether the specified character has a surrogate code unit.

Examples

The following example demonstrates the IsSurrogate method.

using namespace System;
int main()
{
   
   // - escape params specifying Unicode not implemented in v7.0
   Console::WriteLine( Char::IsSurrogate( 'a' ) ); // Output: "False"
}

using System;

public class IsSurrogateSample {
    public static void Main() {
        string str = "\U00010F00"; // Unicode values between 0x10000 and 0x10FFF are represented by two 16-bit "surrogate" characters

        Console.WriteLine(Char.IsSurrogate('a'));		// Output: "False"
        Console.WriteLine(Char.IsSurrogate(str, 0));	// Output: "True"
    }
}

open System

let str = "\U00010F00" // Unicode values between 0x10000 and 0x10FFF are represented by two 16-bit "surrogate" characters

printfn $"{Char.IsSurrogate 'a'}"       // Output: "False"
printfn $"{Char.IsSurrogate(str, 0)}"   // Output: "True"

Module IsSurrogateSample

    Sub Main()

        ' NOTE: Visual Basic doesn't give us a way to create a 32-bit Unicode 
        ' character composed of two 16-bit surrogate values, so a case where 
        ' IsSurrogate returns True cannot be included in this sample. 

        Console.WriteLine(Char.IsSurrogate("a"c))       ' Output: "False"

    End Sub

End Module

IsSurrogate(String, Int32)

Source:

Char.cs

Indicates whether the character at the specified position in a specified string has a surrogate code unit.

public:
 static bool IsSurrogate(System::String ^ s, int index);

public static bool IsSurrogate (string s, int index);

static member IsSurrogate : string * int -> bool

Public Shared Function IsSurrogate (s As String, index As Integer) As Boolean

Parameters

s

String

A string.

index

Int32

The position of the character to evaluate in s.

Returns

Boolean

true if the character at position index in s is a either a high surrogate or a low surrogate; otherwise, false.

Exceptions

ArgumentNullException

s is null.

ArgumentOutOfRangeException

index is less than zero or greater than the last position in s.

Remarks

Character positions in a string are indexed starting from zero.

A surrogate is a Char object with a UTF-16 code unit in the range from U+D800 to U+DFFF. Each character with a code unit in this range belongs to the UnicodeCategory.Surrogate category. The individual surrogate code unit has no interpretation of its own, but has meaning only when used as part of a surrogate pair. For more information about surrogate pairs, see the Unicode Standard at the Unicode home page.

See also

• Rune
• IsHighSurrogate
• IsLowSurrogate
• IsSurrogatePair

IsSurrogate(Char)

Source:

Char.cs

Indicates whether the specified character has a surrogate code unit.

public:
 static bool IsSurrogate(char c);

public static bool IsSurrogate (char c);

static member IsSurrogate : char -> bool

Public Shared Function IsSurrogate (c As Char) As Boolean

Parameters

c

Char

The Unicode character to evaluate.

Returns

Boolean

true if c is either a high surrogate or a low surrogate; otherwise, false.

Remarks

A surrogate is a Char object with a UTF-16 code unit in the range from U+D800 to U+DFFF. Each character with a code unit in this range belongs to the UnicodeCategory.Surrogate category. The individual surrogate code unit has no interpretation of its own, but has meaning only when used as part of a surrogate pair. For more information about surrogate pairs, see the Unicode Standard at the Unicode home page.

See also

• Rune
• IsHighSurrogate
• IsLowSurrogate
• IsSurrogatePair