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Array::Exists<T> Method (array<T>^, Predicate<T>^)

.NET Framework (current version)
 

Determines whether the specified array contains elements that match the conditions defined by the specified predicate.

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

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public:
generic<typename T>
static bool Exists(
	array<T>^ array,
	Predicate<T>^ match
)

Parameters

array
Type: array<T>^

The one-dimensional, zero-based Array to search.

match
Type: System::Predicate<T>^

The Predicate<T> that defines the conditions of the elements to search for.

Return Value

Type: System::Boolean

true if array contains one or more elements that match the conditions defined by the specified predicate; otherwise, false.

Type Parameters

T

The type of the elements of the array.

Exception Condition
ArgumentNullException

array is null.

-or-

match is null.

The Predicate<T> is a delegate to a method that returns true if the object passed to it matches the conditions defined in the delegate. The elements of array are individually passed to the Predicate<T>, and processing is stopped when a match is found.

System_CAPS_noteNote

In C# and Visual Basic, it is not necessary to create the Predicate<T> delegate explicitly. These languages infer the correct delegate from context and create it automatically.

This method is an O(n) operation, where n is the Length of array.

The following example specifies the match conditions for the Exists<T>method usinglambda expressions to check whether a planet starts with a given letter or whether the planet is found on the given array.

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

The following example uses the Exists<T> method to indicate whether any names in a string array begin with a specified character. The example instantiates a StringSearcher object by passing the string to search for to its class constructor. The StringSearcher.StartsWith method has same signature as the Predicate<T> delegate. When theExists<T> method is called, each member of the array is passed to the delegate until it returns true or iterates all the elements in the array.

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

You can also use a lambda expression rather than explicitly define a method whose signature corresponds to that of the delegate. The following example replaces the StringSearcherclass and its StartsWith method with a lambda expression.

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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
Windows Phone Silverlight
Available since 8.0
Windows Phone
Available since 8.1
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