List(T).IndexOf Method (T, Int32, Int32)
Searches for the specified object and returns the zero-based index of the first occurrence within the range of elements in the List(T) that starts at the specified index and contains the specified number of elements.
Assembly: mscorlib (in mscorlib.dll)
- Type: T
The object to locate in the List(T). The value can be a null reference (Nothing in Visual Basic) for reference types.
- Type: System.Int32
The zero-based starting index of the search. 0 (zero) is valid in an empty list.
- Type: System.Int32
The number of elements in the section to search.
The List(T) is searched forward starting at index and ending at index plus count minus 1, if count is greater than 0.
This method determines equality using the default equality comparer EqualityComparer(T).Default for T, the type of values in the list.
This method performs a linear search; therefore, this method is an O(n) operation, where n is count.
The following code example demonstrates all three overloads of the IndexOf method. A List(T) of strings is created, with one entry that appears twice, at index location 0 and index location 5. The IndexOf(T) method overload searches the list from the beginning, and finds the first occurrence of the string. The IndexOf(T, Int32) method overload is used to search the list beginning with index location 3 and continuing to the end of the list, and finds the second occurrence of the string. Finally, the method overload is used to search a range of two entries, beginning at index location two; it returns –1 because there are no instances of the search string in that range.
Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune
The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.