CompareInfo::IndexOf Method (String^, String^)
Searches for the specified substring and returns the zero-based index of the first occurrence within the entire source string.
Assembly: mscorlib (in mscorlib.dll)
Parameters
- source
-
Type:
System::String^
The string to search.
- value
-
Type:
System::String^
The string to locate within source.
Return Value
Type: System::Int32The zero-based index of the first occurrence of value, if found, within source; otherwise, -1. Returns 0 (zero) if value is an ignorable character.
| Exception | Condition |
|---|---|
| ArgumentNullException | source is null. -or- value is null. |
The source string is searched forward starting at the beginning of the string and ending at the end 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, you should use one of the overloads that has a parameter of type CompareOptions and use the Ordinal value.
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, 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 IndexOf(String^, String^) method always returns 0 (zero) to indicate that the match is found at the beginning of source. In the following example, the IndexOf(String^, String^) 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. In each case, because the soft hyphen is an ignorable character, the result is the same as if the soft hyphen had not been included in value. When searching for a soft hyphen only, the method returns 0 (zero) to indicate that it has found a match at the beginning of the 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
