Collection<T>.IList.IndexOf(Object) Method

Reference

Definition

Namespace:: System.Collections.ObjectModel

Assembly:: System.Runtime.dll

Assembly:: mscorlib.dll

Assembly:: netstandard.dll

Important

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Determines the index of a specific item in the IList.

 virtual int System.Collections.IList.IndexOf(System::Object ^ value) = System::Collections::IList::IndexOf;

int IList.IndexOf (object value);

abstract member System.Collections.IList.IndexOf : obj -> int
override this.System.Collections.IList.IndexOf : obj -> int

Function IndexOf (value As Object) As Integer Implements IList.IndexOf

Parameters

value: Object

The Object to locate in the IList.

Returns

Int32

The index of value if found in the list; otherwise, -1.

Implements

IndexOf(Object)

Exceptions

ArgumentException

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

Remarks

This method determines equality using the default comparer Comparer<T>.Default. Comparer<T>.Default checks whether type T implements System.IComparable<T> and uses that implementation, if available. If not, Comparer<T>.Default checks whether type T implements System.IComparable. If type T does not implement either interface, this method uses Object.Equals.

This method is an O(n) operation, where n is Count.

Applies to