System.String.IndexOf Method

Reports the zero-based index of the first occurrence of the specified string in the current string object. Parameters specify the starting search position in the current string and the type of search to use for the specified string.


public int IndexOf (string value, int startIndex, StringComparison comparisonType)


The string to seek.
The search starting position.
One of the enumeration values that specifies the rules for the search.


The zero-based index position of the value parameter if that string is found, or -1 if it is not. If value is string.Empty, the return value is startIndex.


Index numbering starts from 0. The startIndex parameter can range from 0 to the length of the string instance. If startIndex equals the length of the string instance, the method returns -1.

The comparisonType parameter specifies to search for the value parameter using the current or invariant culture, using a case-sensitive or case-insensitive search, and using word or ordinal comparison rules.


Namespace: System
Assembly: mscorlib (in mscorlib.dll)
Assembly Versions:,
Since: .NET 2.0