Enumerable.FirstOrDefault(TSource) Method (IEnumerable(TSource), Func(TSource, Boolean))

Returns the first element of the sequence that satisfies a condition or a default value if no such element is found.

Namespace:  System.Linq
Assembly:  System.Core (in System.Core.dll)

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

Type Parameters

TSource

The type of the elements of source.

Parameters

source
Type: System.Collections.Generic.IEnumerable(TSource)
An IEnumerable(T) to return an element from.
predicate
Type: System.Func(TSource, Boolean)
A function to test each element for a condition.

Return Value

Type: TSource
default(TSource) if source is empty or if no element passes the test specified by predicate; otherwise, the first element in source that passes the test specified by predicate.

Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type IEnumerable(TSource). When you use instance method syntax to call this method, omit the first parameter.

ExceptionCondition
ArgumentNullException

source or predicate is a null reference (Nothing in Visual Basic).

The default value for reference and nullable types is a null reference (Nothing in Visual Basic).

The following code example demonstrates how to use FirstOrDefault(TSource)(IEnumerable(TSource), Func(TSource, Boolean)) by passing in a predicate. In the second call to the method, there is no element in the array that satisfies the condition.

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

Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

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