CompareInfo.LastIndexOf Method (String, String)

Searches for the specified substring and returns the zero-based index of the last occurrence within the entire source string.

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

public virtual int LastIndexOf(
	string source,
	string value
)

Parameters

source
Type: System.String

The string to search.

value
Type: System.String

The string to locate within source.

Return Value

Type: System.Int32
The zero-based index of the last occurrence of value within the entire source, if found; otherwise, -1.

ExceptionCondition
ArgumentNullException

source is null.

-or-

value is null.

The source string is searched backward starting at the end of the string and ending at the beginning of the string.

This overload performs a culture-sensitive search. A Unicode value representing a precomposed character, such as the ligature "Æ" (U+00C6), might be considered equivalent to any occurrence of the character's components in the correct sequence, such as "AE" (U+0041, U+0045), depending on the culture. To perform an ordinal (culture-insensitive) search, where the Unicode values are compared, the application should use one of the overloads that accepts a CompareOptions value as a parameter and use the Ordinal value.

The following code example determines the indexes of the first and last occurrences of a character or a substring within a string.

using System;
using System.Globalization;

public class SamplesCompareInfo  {

   public static void Main()  {

      // Creates CompareInfo for the InvariantCulture.
      CompareInfo myComp = CultureInfo.InvariantCulture.CompareInfo;

      // Searches for the ligature Æ.
      String myStr = "Is AE or ae the same as Æ or æ?";
      Console.WriteLine();
      Console.WriteLine( "No options    : {0}", myStr );
      PrintMarker( "           AE : ", myComp.IndexOf( myStr, "AE" ), myComp.LastIndexOf( myStr, "AE" ) );
      PrintMarker( "           ae : ", myComp.IndexOf( myStr, "ae" ), myComp.LastIndexOf( myStr, "ae" ) );
      PrintMarker( "            Æ : ", myComp.IndexOf( myStr, 'Æ' ), myComp.LastIndexOf( myStr, 'Æ' ) );
      PrintMarker( "            æ : ", myComp.IndexOf( myStr, 'æ' ), myComp.LastIndexOf( myStr, 'æ' ) );
      Console.WriteLine( "Ordinal       : {0}", myStr );
      PrintMarker( "           AE : ", myComp.IndexOf( myStr, "AE", CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, "AE", CompareOptions.Ordinal ) );
      PrintMarker( "           ae : ", myComp.IndexOf( myStr, "ae", CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, "ae", CompareOptions.Ordinal ) );
      PrintMarker( "            Æ : ", myComp.IndexOf( myStr, 'Æ', CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, 'Æ', CompareOptions.Ordinal ) );
      PrintMarker( "            æ : ", myComp.IndexOf( myStr, 'æ', CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, 'æ', CompareOptions.Ordinal ) );
      Console.WriteLine( "IgnoreCase    : {0}", myStr );
      PrintMarker( "           AE : ", myComp.IndexOf( myStr, "AE", CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, "AE", CompareOptions.IgnoreCase ) );
      PrintMarker( "           ae : ", myComp.IndexOf( myStr, "ae", CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, "ae", CompareOptions.IgnoreCase ) );
      PrintMarker( "            Æ : ", myComp.IndexOf( myStr, 'Æ', CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, 'Æ', CompareOptions.IgnoreCase ) );
      PrintMarker( "            æ : ", myComp.IndexOf( myStr, 'æ', CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, 'æ', CompareOptions.IgnoreCase ) );

      // Searches for the combining character sequence Latin capital letter U with diaeresis or Latin small letter u with diaeresis.
      myStr = "Is \u0055\u0308 or \u0075\u0308 the same as \u00DC or \u00FC?";
      Console.WriteLine();
      Console.WriteLine( "No options    : {0}", myStr );
      PrintMarker( "           U\u0308 : ", myComp.IndexOf( myStr, "U\u0308" ), myComp.LastIndexOf( myStr, "U\u0308" ) );
      PrintMarker( "           u\u0308 : ", myComp.IndexOf( myStr, "u\u0308" ), myComp.LastIndexOf( myStr, "u\u0308" ) );
      PrintMarker( "            Ü : ", myComp.IndexOf( myStr, 'Ü' ), myComp.LastIndexOf( myStr, 'Ü' ) );
      PrintMarker( "            ü : ", myComp.IndexOf( myStr, 'ü' ), myComp.LastIndexOf( myStr, 'ü' ) );
      Console.WriteLine( "Ordinal       : {0}", myStr );
      PrintMarker( "           U\u0308 : ", myComp.IndexOf( myStr, "U\u0308", CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, "U\u0308", CompareOptions.Ordinal ) );
      PrintMarker( "           u\u0308 : ", myComp.IndexOf( myStr, "u\u0308", CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, "u\u0308", CompareOptions.Ordinal ) );
      PrintMarker( "            Ü : ", myComp.IndexOf( myStr, 'Ü', CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, 'Ü', CompareOptions.Ordinal ) );
      PrintMarker( "            ü : ", myComp.IndexOf( myStr, 'ü', CompareOptions.Ordinal ), myComp.LastIndexOf( myStr, 'ü', CompareOptions.Ordinal ) );
      Console.WriteLine( "IgnoreCase    : {0}", myStr );
      PrintMarker( "           U\u0308 : ", myComp.IndexOf( myStr, "U\u0308", CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, "U\u0308", CompareOptions.IgnoreCase ) );
      PrintMarker( "           u\u0308 : ", myComp.IndexOf( myStr, "u\u0308", CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, "u\u0308", CompareOptions.IgnoreCase ) );
      PrintMarker( "            Ü : ", myComp.IndexOf( myStr, 'Ü', CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, 'Ü', CompareOptions.IgnoreCase ) );
      PrintMarker( "            ü : ", myComp.IndexOf( myStr, 'ü', CompareOptions.IgnoreCase ), myComp.LastIndexOf( myStr, 'ü', CompareOptions.IgnoreCase ) );

   }

   public static void PrintMarker( String Prefix, int First, int Last )  {

      // Determines the size of the array to create. 
      int mySize;
      if ( Last > First )
         mySize = Last;
      else
         mySize = First;

      if ( mySize > -1 )  {

         // Creates an array of Char to hold the markers.
         Char[] myCharArr = new Char[mySize+1];

         // Inserts the appropriate markers. 
         if ( First > -1 )
         myCharArr[First] = 'f';
         if ( Last > -1 )
            myCharArr[Last] = 'l';
         if ( First == Last )
         myCharArr[First] = 'b';

         // Displays the array of Char as a String.
         Console.WriteLine( "{0}{1}", Prefix, new String( myCharArr ) );

      }
      else
         Console.WriteLine( Prefix );

   }

}


/*
This code produces the following output.

No options    : Is AE or ae the same as Æ or æ?
           AE :    f                    l
           ae :          f                   l
            Æ :    f                    l
            æ :          f                   l
Ordinal       : Is AE or ae the same as Æ or æ?
           AE :    b
           ae :          b
            Æ :                         b
            æ :                              b
IgnoreCase    : Is AE or ae the same as Æ or æ?
           AE :    f                         l
           ae :    f                         l
            Æ :    f                         l
            æ :    f                         l

No options    : Is U" or u" the same as Ü or ü?
           U" :    f                    l
           u" :          f                   l
            Ü :    f                    l
            ü :          f                   l
Ordinal       : Is U" or u" the same as Ü or ü?
           U" :    b
           u" :          b
            Ü :                         b
            ü :                              b
IgnoreCase    : Is U" or u" the same as Ü or ü?
           U" :    f                         l
           u" :    f                         l
            Ü :    f                         l
            ü :    f                         l

*/

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, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

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.

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 3.5, 2.0, 1.0

XNA Framework

Supported in: 3.0, 2.0, 1.0
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