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List<T>.IList.IndexOf Method

Determines the index of a specific item in the IList.

Namespace:  System.Collections.Generic
Assemblies:   mscorlib (in mscorlib.dll)
  System.Collections (in System.Collections.dll)

int IList.IndexOf(
	Object item
)

Parameters

item
Type: System.Object

The object to locate in the IList.

Return Value

Type: System.Int32
The index of item if found in the list; otherwise, –1.

Implements

IList.IndexOf(Object)

ExceptionCondition
ArgumentException

item is of a type that is not assignable to the IList.

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.

.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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