List<'T>.Contains Method ('T)

 

Determines whether an element is in the List<'T>.

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

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

Parameters

item
Type: T

The object to locate in the List<'T>. The value can be null 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.

Universal Windows Platform
Available since 8
.NET Framework
Available since 2.0
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
Return to top
Show: