String.ToUpperInvariant Method (System)

.NET Framework Class Library

String..::.ToUpperInvariant Method

Updated: October 2008

Returns a copy of this String object converted to uppercase using the casing rules of the invariant culture.

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

Syntax

Visual Basic (Declaration)

Public Function ToUpperInvariant As String

Visual Basic (Usage)

Dim instance As String
Dim returnValue As String

returnValue = instance.ToUpperInvariant()

public string ToUpperInvariant()

Visual C++

public:
String^ ToUpperInvariant()

JScript

public function ToUpperInvariant() : String

Return Value

Type: System..::.String
A String object in uppercase.

Remarks

The invariant culture represents a culture that is culture-insensitive. It is associated with the English language but not with a specific country or region. For details, see Using the InvariantCulture Property.

If your application depends on the case of a string changing in a predictable way that is unaffected by the current culture, use the ToUpperInvariant method. The ToUpperInvariant method is equivalent to ToUpper(CultureInfo.InvariantCulture).

Note:
This method does not modify the value of the current instance. Instead, it returns a new string in which all characters in the current instance are uppercased.

Security Considerations

If you need the lowercase or uppercase version of an operating system identifier, such as a file name, named pipe, or registry key, use the ToLowerInvariant or ToUpperInvariant methods.

Examples

The following example converts a string of lowercase characters to two strings of uppercase characters using the English-United States and Turkish-Turkey cultures, then compares the uppercase strings. The uppercase strings are identical except that for each occurrence of the Unicode LATIN CAPITAL LETTER I in one string, the other string contains LATIN CAPITAL LETTER I WITH DOT ABOVE.

Visual Basic

' Sample for String.ToUpper(CultureInfo)
Imports System
Imports System.Globalization
Imports Microsoft.VisualBasic

Class Sample

   Public Shared Sub Main()
      Dim str1 As [String] = "indigo"
      Dim str2, str3 As [String]

      Console.WriteLine()
      Console.WriteLine("str1 = '{0}'", str1)

      Console.WriteLine("str2 = Upper case copy of str1 using English-United States culture.")
      ' str2 is an upper case copy of str1, using English-United States culture.
      str2 = str1.ToUpper(New CultureInfo("en-US", False))

      ' str3 is an upper case copy of str1, using Turkish-Turkey culture.
      Console.WriteLine("str3 = Upper case copy of str1 using Turkish-Turkey culture.")
      str3 = str1.ToUpper(New CultureInfo("tr-TR", False))

      ' Compare the code points in str2 and str3.
      Console.WriteLine()
      Console.WriteLine("str2 is {0} to str3.", IIf(0 = [String].CompareOrdinal(str2, str3), "equal", "not equal"))
      CodePoints("str1", str1)
      CodePoints("str2", str2)
      CodePoints("str3", str3)
   End Sub 'Main

   Public Shared Sub CodePoints(title As [String], s As [String])
      Console.Write("{0}The code points in {1} are: {0}", Environment.NewLine, title)
      Dim c As Char
      For Each c In  s
         Console.Write("{0:x4} ", AscW(c))
      Next c
      Console.WriteLine()
   End Sub 'CodePoints
End Class 'Sample
'
'This example produces the following results:
'
'str1 = 'indigo'
'str2 = Upper case copy of str1 using English-United States culture.
'str3 = Upper case copy of str1 using Turkish-Turkey culture.
'
'str2 is not equal to str3.
'
'The code points in str1 are:
'0069 006e 0064 0069 0067 006f
'
'The code points in str2 are:
'0049 004e 0044 0049 0047 004f
'
'The code points in str3 are:
'0130 004e 0044 0130 0047 004f
'

// Sample for String.ToUpper(CultureInfo)
using System;
using System.Globalization;

class Sample 
{
    public static void Main() 
    {
    String str1 = "indigo";
    String str2, str3;

    Console.WriteLine();
    Console.WriteLine("str1 = '{0}'", str1);

    Console.WriteLine("str2 = Upper case copy of str1 using English-United States culture.");
    // str2 is an upper case copy of str1, using English-United States culture.
    str2 = str1.ToUpper(new CultureInfo("en-US", false));

    // str3 is an upper case copy of str1, using Turkish-Turkey culture.
    Console.WriteLine("str3 = Upper case copy of str1 using Turkish-Turkey culture.");
    str3 = str1.ToUpper(new CultureInfo("tr-TR", false));

    // Compare the code points in str2 and str3.
    Console.WriteLine();
    Console.WriteLine("str2 is {0} to str3.", 
         ((0 == String.CompareOrdinal(str2, str3)) ? "equal" : "not equal"));
    CodePoints("str1", str1);
    CodePoints("str2", str2);
    CodePoints("str3", str3);
    }

    public static void CodePoints(String title, String s)
    {
    Console.Write("{0}The code points in {1} are: {0}", Environment.NewLine, title);
    foreach (ushort u in s)
      Console.Write("{0:x4} ", u);
    Console.WriteLine();
    }
}
/*
This example produces the following results:

str1 = 'indigo'
str2 = Upper case copy of str1 using English-United States culture.
str3 = Upper case copy of str1 using Turkish-Turkey culture.

str2 is not equal to str3.

The code points in str1 are:
0069 006e 0064 0069 0067 006f

The code points in str2 are:
0049 004e 0044 0049 0047 004f

The code points in str3 are:
0130 004e 0044 0130 0047 004f
*/

Visual C++

// Sample for String::ToUpper(CultureInfo)
using namespace System;
using namespace System::Globalization;
void CodePoints( String^ title, String^ s )
{
   Console::Write( " {0}The code points in {1} are: {0}", Environment::NewLine, title );
   System::Collections::IEnumerator^ myEnum = s->GetEnumerator();
   while ( myEnum->MoveNext() )
   {
      UInt16 u = safe_cast<Char>(myEnum->Current);
      Console::Write( "{0:x4} ", u );
   }

   Console::WriteLine();
}

int main()
{
   String^ str1 = "indigo";
   String^ str2;
   String^ str3;
   Console::WriteLine();
   Console::WriteLine( "str1 = ' {0}'", str1 );
   Console::WriteLine( "str2 = Upper case copy of str1 using English-United States culture." );

   // str2 is an upper case copy of str1, using English-United States culture.
   str2 = str1->ToUpper( gcnew CultureInfo( "en-US",false ) );

   // str3 is an upper case copy of str1, using Turkish-Turkey culture.
   Console::WriteLine( "str3 = Upper case copy of str1 using Turkish-Turkey culture." );
   str3 = str1->ToUpper( gcnew CultureInfo( "tr-TR",false ) );

   // Compare the code points in str2 and str3.
   Console::WriteLine();
   Console::WriteLine( "str2 is {0} to str3.", ((0 == String::CompareOrdinal( str2, str3 )) ? (String^)"equal" : "not equal") );
   CodePoints( "str1", str1 );
   CodePoints( "str2", str2 );
   CodePoints( "str3", str3 );
}

/*
This example produces the following results:

str1 = 'indigo'
str2 = Upper case copy of str1 using English-United States culture.
str3 = Upper case copy of str1 using Turkish-Turkey culture.

str2 is not equal to str3.

The code points in str1 are:
0069 006e 0064 0069 0067 006f

The code points in str2 are:
0049 004e 0044 0049 0047 004f

The code points in str3 are:
0130 004e 0044 0130 0047 004f
*/

Platforms

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Version Information