EnumerableExtensionsTryFirstTSource - метод

public static bool TryFirst<TSource>(
	this IEnumerable<TSource> source,
	Func<TSource, bool> predicate,
	out TSource item
)

<ExtensionAttribute>
Public Shared Function TryFirst(Of TSource) ( 
	source As IEnumerable(Of TSource),
	predicate As Func(Of TSource, Boolean),
	<OutAttribute> ByRef item As TSource
) As Boolean

public:
[ExtensionAttribute]
generic<typename TSource>
static bool TryFirst(
	IEnumerable<TSource>^ source, 
	Func<TSource, bool>^ predicate, 
	[OutAttribute] TSource% item
)

[<ExtensionAttribute>]
static member TryFirst : 
        source : IEnumerable<'TSource> * 
        predicate : Func<'TSource, bool> * 
        item : 'TSource byref -> bool