Searches for the specified character and returns the zero-based index of the last occurrence within the section of the source string that contains the specified number of elements and ends at the specified index.
Syntax
Parameters
- source
- value
- startIndex
- count
Returns
The zero-based index of the last occurrence of value, if found, within the section of source that contains the number of elements specified by count and that ends at startIndex; otherwise, -1. Returns startIndex if value is an ignorable character.
Remarks
The source string is searched backward starting at startIndex and ending at startIndex - count + 1.
This overload performs a culture-sensitive search. If the character is a Unicode value representing a precomposed character, such as the ligature "Æ" (U+00C6), it might be considered equivalent to any occurrence of its components in the correct sequence, such as "AE" (U+0041, U+0045), depending on the culture. To perform an ordinal (culture-insensitive) search, where a character is considered equivalent to another character only if the Unicode values are the same, you should call one of the overloads that has a parameter of type System.Globalization.CompareOptions and use the CompareOptions.Ordinal value. Overloads of string.LastIndexOf(char) that search for a character perform an ordinal search, whereas those that search for a string perform a culture-sensitive search.
When possible, you should call string comparison methods that have a parameter of type System.Globalization.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.
Requirements
Assembly: mscorlib (in mscorlib.dll)
Assembly Versions: 1.0.5000.0, 2.0.0.0, 4.0.0.0