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Enumerable::FirstOrDefault<TSource> Method (IEnumerable<TSource>, Func<TSource, Boolean>)
Visual Studio 2008
Returns the first element of the sequence that satisfies a condition or a default value if no such element is found.
Assembly: System.Core (in System.Core.dll)
[ExtensionAttribute] public: generic<typename TSource> static TSource FirstOrDefault( IEnumerable<TSource>^ source, Func<TSource, bool>^ predicate )
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: TSourcedefault(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. For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).| Exception | Condition |
|---|---|
| ArgumentNullException | source or predicate is nullptr. |
Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune
The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
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