CompareInfo::IndexOf Method (String^, String^, CompareOptions)
Searches for the specified substring and returns the zero-based index of the first occurrence within the entire source string using the specified CompareOptions value.
Assembly: mscorlib (in mscorlib.dll)
Parameters
- source
-
Type:
System::String^
The string to search.
- value
-
Type:
System::String^
The string to locate within source.
- options
-
Type:
System.Globalization::CompareOptions
A value that defines how source and value should be compared. options is either the enumeration value Ordinal, or a bitwise combination of one or more of the following values: IgnoreCase, IgnoreSymbols, IgnoreNonSpace, IgnoreWidth, and IgnoreKanaType.
Return Value
Type: System::Int32The zero-based index of the first occurrence of value, if found, within source, using the specified comparison options; otherwise, -1. Returns 0 (zero) if value is an ignorable character.
| Exception | Condition |
|---|---|
| ArgumentNullException | source is null. -or- value is null. |
| ArgumentException | options contains an invalid CompareOptions value. |
The source string is searched forward starting at the beginning of the string and ending at the end of the string.
The CompareOptions::StringSort value is not valid for this method.
If options does not include the Ordinal value, 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. If options includes the Ordinal value, this overload performs an ordinal (culture-insensitive) search, where the Unicode values are compared.
Note |
|---|
When possible, you should call string comparison methods that have a parameter of type CompareOptions to specify the kind of comparison expected. As a general rule, use linguistic options (using the current culture) for comparing strings displayed in the user interface and specify CompareOptions::Ordinal or CompareOptions::OrdinalIgnoreCase for security comparisons. |
Notes to Callers:
Character sets include ignorable characters, which are characters that are not considered when performing a linguistic or culture-sensitive sort. In a culture-sensitive search (that is, if options is not CompareOptions::Ordinal or CompareOptions::OrdinalIgnoreCase), if value contains an ignorable character, the result is equivalent to searching with that character removed. If value consists only of one or more ignorable characters, the CompareInfo::IndexOf method always returns 0 (zero) to indicate that the match is found at the beginning of source. In the following example, the CompareInfo::IndexOf method is used to find three substrings (a soft hyphen (U+00AD), a soft hyphen followed by "n", and a soft hyphen followed by "m") in two strings. Only one of the strings contains a soft hyphen. Because the soft hyphen is an ignorable character, a culture-sensitive search returns the same value that it would return if the soft hyphen were not included in the search string. An ordinal search, however, successfully finds the soft hyphen in one string and reports that it is absent from the second string.
The following example determines the indexes of the first and last occurrences of a character or a substring within a string.
using namespace System; using namespace System::Globalization; 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. array<Char>^myCharArr = gcnew array<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, gcnew String( myCharArr ) ); } else Console::WriteLine( Prefix ); } int 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, L'Æ' ), myComp->LastIndexOf( myStr, L'Æ' ) ); PrintMarker( " æ : ", myComp->IndexOf( myStr, L'æ' ), myComp->LastIndexOf( myStr, L'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, L'Æ', CompareOptions::Ordinal ), myComp->LastIndexOf( myStr, L'Æ', CompareOptions::Ordinal ) ); PrintMarker( " æ : ", myComp->IndexOf( myStr, L'æ', CompareOptions::Ordinal ), myComp->LastIndexOf( myStr, L'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, L'Æ', CompareOptions::IgnoreCase ), myComp->LastIndexOf( myStr, L'Æ', CompareOptions::IgnoreCase ) ); PrintMarker( " æ : ", myComp->IndexOf( myStr, L'æ', CompareOptions::IgnoreCase ), myComp->LastIndexOf( myStr, L'æ', CompareOptions::IgnoreCase ) ); // Searches for the combining character sequence Latin capital letter U with diaeresis or Latin small letter u with diaeresis. myStr = "Is U\u0308 or u\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, L'Ü' ), myComp->LastIndexOf( myStr, L'Ü' ) ); PrintMarker( " ü : ", myComp->IndexOf( myStr, L'ü' ), myComp->LastIndexOf( myStr, L'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, L'Ü', CompareOptions::Ordinal ), myComp->LastIndexOf( myStr, L'Ü', CompareOptions::Ordinal ) ); PrintMarker( " ü : ", myComp->IndexOf( myStr, L'ü', CompareOptions::Ordinal ), myComp->LastIndexOf( myStr, L'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, L'Ü', CompareOptions::IgnoreCase ), myComp->LastIndexOf( myStr, L'Ü', CompareOptions::IgnoreCase ) ); PrintMarker( " ü : ", myComp->IndexOf( myStr, L'ü', CompareOptions::IgnoreCase ), myComp->LastIndexOf( myStr, L'ü', CompareOptions::IgnoreCase ) ); } /* 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 */
Available since 8
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
