• Article

ReadOnlyCollection<T>.IndexOf Method

Microsoft Silverlight will reach end of support after October 2021. Learn more.

Searches for the specified object and returns the zero-based index of the first occurrence within the entire ReadOnlyCollection<T>.

Namespace:  System.Collections.ObjectModel
Assembly:  mscorlib (in mscorlib.dll)

Syntax

'Declaration
Public Function IndexOf ( _
    value As T _
) As Integer

public int IndexOf(
    T value
)

Parameters

  • value
    Type: T
    The object to locate in the List<T>. The value can be nulla null reference (Nothing in Visual Basic) for reference types.

Return Value

Type: System.Int32
The zero-based index of the first occurrence of item within the entire ReadOnlyCollection<T>, if found; otherwise, -1.

Implements

IList<T>.IndexOf(T)

Remarks

The ReadOnlyCollection<T> is searched forward starting at the first element and ending at the last element.

This method determines equality using the default comparer EqualityComparer<T>.Default.

This method performs a linear search; therefore, this method is an O(n) operation, where n is Count.

Version Information

Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.