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String::IsNormalized Method

Indicates whether this string is in Unicode normalization form C.

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

public:
bool IsNormalized()

Return Value

Type: System::Boolean
true if this string is in normalization form C; otherwise, false.

ExceptionCondition
ArgumentException

The current instance contains invalid Unicode characters.

Some Unicode characters have multiple equivalent binary representations consisting of sets of combining and/or composite Unicode characters. The existence of multiple representations for a single character complicates searching, sorting, matching, and other operations.

The Unicode standard defines a process called normalization that returns one binary representation when given any of the equivalent binary representations of a character. Normalization can be performed with several algorithms, called normalization forms, that obey different rules. The .NET Framework currently supports normalization forms C, D, KC, and KD.

For a description of supported Unicode normalization forms, see System.Text::NormalizationForm.

Notes to Callers

The IsNormalized method returns false as soon as it encounters the first non-normalized character in a string. Therefore, if a string contains non-normalized characters followed by invalid Unicode characters, the Normalize method will throw an ArgumentException although IsNormalized returns false.

The following example determines whether a string is successfully normalized to various normalization forms.

using namespace System;
using namespace System::Text;

void Show( String^ title, String^ s )
{
   Console::Write( "Characters in string {0} = ", title );
   for each (short x in s) {
      Console::Write("{0:X4} ", x);
   }
   Console::WriteLine();
}

int main()
{

   // Character c; combining characters acute and cedilla; character 3/4 
   array<Char>^temp0 = {L'c',L'\u0301',L'\u0327',L'\u00BE'};
   String^ s1 = gcnew String( temp0 );
   String^ s2 = nullptr;
   String^ divider = gcnew String( '-',80 );
   divider = String::Concat( Environment::NewLine, divider, Environment::NewLine );

   Show( "s1", s1 );
   Console::WriteLine();
   Console::WriteLine( "U+0063 = LATIN SMALL LETTER C" );
   Console::WriteLine( "U+0301 = COMBINING ACUTE ACCENT" );
   Console::WriteLine( "U+0327 = COMBINING CEDILLA" );
   Console::WriteLine( "U+00BE = VULGAR FRACTION THREE QUARTERS" );
   Console::WriteLine( divider );
   Console::WriteLine( "A1) Is s1 normalized to the default form (Form C)?: {0}", s1->IsNormalized() );
   Console::WriteLine( "A2) Is s1 normalized to Form C?:  {0}", s1->IsNormalized( NormalizationForm::FormC ) );
   Console::WriteLine( "A3) Is s1 normalized to Form D?:  {0}", s1->IsNormalized( NormalizationForm::FormD ) );
   Console::WriteLine( "A4) Is s1 normalized to Form KC?: {0}", s1->IsNormalized( NormalizationForm::FormKC ) );
   Console::WriteLine( "A5) Is s1 normalized to Form KD?: {0}", s1->IsNormalized( NormalizationForm::FormKD ) );
   Console::WriteLine( divider );
   Console::WriteLine( "Set string s2 to each normalized form of string s1." );
   Console::WriteLine();
   Console::WriteLine( "U+1E09 = LATIN SMALL LETTER C WITH CEDILLA AND ACUTE" );
   Console::WriteLine( "U+0033 = DIGIT THREE" );
   Console::WriteLine( "U+2044 = FRACTION SLASH" );
   Console::WriteLine( "U+0034 = DIGIT FOUR" );
   Console::WriteLine( divider );
   s2 = s1->Normalize();
   Console::Write( "B1) Is s2 normalized to the default form (Form C)?: " );
   Console::WriteLine( s2->IsNormalized() );
   Show( "s2", s2 );
   Console::WriteLine();
   s2 = s1->Normalize( NormalizationForm::FormC );
   Console::Write( "B2) Is s2 normalized to Form C?: " );
   Console::WriteLine( s2->IsNormalized( NormalizationForm::FormC ) );
   Show( "s2", s2 );
   Console::WriteLine();
   s2 = s1->Normalize( NormalizationForm::FormD );
   Console::Write( "B3) Is s2 normalized to Form D?: " );
   Console::WriteLine( s2->IsNormalized( NormalizationForm::FormD ) );
   Show( "s2", s2 );
   Console::WriteLine();
   s2 = s1->Normalize( NormalizationForm::FormKC );
   Console::Write( "B4) Is s2 normalized to Form KC?: " );
   Console::WriteLine( s2->IsNormalized( NormalizationForm::FormKC ) );
   Show( "s2", s2 );
   Console::WriteLine();
   s2 = s1->Normalize( NormalizationForm::FormKD );
   Console::Write( "B5) Is s2 normalized to Form KD?: " );
   Console::WriteLine( s2->IsNormalized( NormalizationForm::FormKD ) );
   Show( "s2", s2 );
   Console::WriteLine();
}

/*
This example produces the following results:

Characters in string s1 = 0063 0301 0327 00BE

U+0063 = LATIN SMALL LETTER C
U+0301 = COMBINING ACUTE ACCENT
U+0327 = COMBINING CEDILLA
U+00BE = VULGAR FRACTION THREE QUARTERS

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

A1) Is s1 normalized to the default form (Form C)?: False
A2) Is s1 normalized to Form C?:  False
A3) Is s1 normalized to Form D?:  False
A4) Is s1 normalized to Form KC?: False
A5) Is s1 normalized to Form KD?: False

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

Set string s2 to each normalized form of string s1.

U+1E09 = LATIN SMALL LETTER C WITH CEDILLA AND ACUTE
U+0033 = DIGIT THREE
U+2044 = FRACTION SLASH
U+0034 = DIGIT FOUR

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

B1) Is s2 normalized to the default form (Form C)?: True
Characters in string s2 = 1E09 00BE

B2) Is s2 normalized to Form C?: True
Characters in string s2 = 1E09 00BE

B3) Is s2 normalized to Form D?: True
Characters in string s2 = 0063 0327 0301 00BE

B4) Is s2 normalized to Form KC?: True
Characters in string s2 = 1E09 0033 2044 0034

B5) Is s2 normalized to Form KD?: True
Characters in string s2 = 0063 0327 0301 0033 2044 0034

*/

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1
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