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 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.
.NET FrameworkSupported in: 4.5, 4, 3.5, 3.0, 2.0
.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 Silverlight 8.1, Windows Phone Silverlight 8
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)
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.