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IndexOf Method

ReadOnlyCollection<T>.IndexOf Method

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)

public int IndexOf(
	T value
)

Parameters

value
Type: T

The object to locate in the List<T>. The value can be null 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)

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.

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

XNA Framework

Supported in: 3.0, 2.0, 1.0

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone Silverlight 8.1, Windows Phone Silverlight 8

Portable Class Library

Supported in: Portable Class Library
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