IsSurrogate Method (String, Int32)
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Char.IsSurrogate Method (String, Int32)

[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]

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

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

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

Parameters

s
Type: System.String
A string.
index
Type: System.Int32
The character position in s.

Return Value

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

ExceptionCondition
ArgumentNullException

s is Nothing.

ArgumentOutOfRangeException

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

Character positions in a string are indexed starting from zero.

A surrogate is a Char object with a Unicode 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.

The following example demonstrates IsSurrogate.



Module Example

   Public Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)

      ' 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. 

      outputBlock.Text &= Char.IsSurrogate("a"c) & vbCrLf       ' Output: "False"

   End Sub

End Module


Windows Phone OS

Supported in: 8.1, 8.0, 7.1, 7.0

Windows Phone

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