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List(T).Contains Method

Determines whether an element is in the List(T).

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

abstract Contains : 
        item:'T -> bool  
override Contains : 
        item:'T -> bool


Type: T

The object to locate in the List(T). The value can be a null reference (Nothing in Visual Basic) for reference types.

Return Value

Type: System.Boolean
true if item is found in the List(T); otherwise, false.



This method determines equality by using the default equality comparer, as defined by the object's implementation of the IEquatable(T).Equals method 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 the Contains and Existsmethods on a List(T) that contains a simple business object that implements Equals.

No code example is currently available or this language may not be supported.

The following example contains a list of complex objects of type Cube. The Cube class implements the IEquatable(T).Equals method so that two cubes are considered equal if their dimensions are the same. In this example, the Contains method returns true, because a cube that has the specified dimensions is already in the collection.

No code example is currently available or this language may not be supported.

.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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