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.
Assembly: mscorlib (in mscorlib.dll)
abstract LastIndexOf : source:string * value:string -> int override LastIndexOf : source:string * value:string -> int
- Type: System.String
The string to search.
- Type: System.String
The string to locate within source.
Return ValueType: System.Int32
The zero-based index of the last occurrence of value, if found, within source; otherwise, -1.
source is a null reference (Nothing in Visual Basic).
value is a null reference (Nothing in Visual Basic).
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, you should call one of the overloads that has a parameter of type CompareOptions and use the CompareOptions.Ordinal value.
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.
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 method always returns source.Length – 1, which represents the last index position in source. In the following example, the 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 6 and 5. These values correspond to the index of the last character in the two strings.
.NET FrameworkSupported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0
.NET Framework Client ProfileSupported in: 4, 3.5 SP1
Portable Class LibrarySupported in: Portable Class Library
.NET for Windows Store appsSupported in: Windows 8
.NET for Windows Phone appsSupported in: Windows Phone 8.1, Windows Phone 8, Silverlight 8.1
Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)