Enumerable.TryGetNonEnumeratedCount<TSource> Method
Definition
Important
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Attempts to determine the number of elements in a sequence without forcing an enumeration.
public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
static bool TryGetNonEnumeratedCount(System::Collections::Generic::IEnumerable<TSource> ^ source, [Runtime::InteropServices::Out] int % count);public static bool TryGetNonEnumeratedCount<TSource> (this System.Collections.Generic.IEnumerable<TSource> source, out int count);static member TryGetNonEnumeratedCount : seq<'Source> * int -> bool<Extension()>
Public Function TryGetNonEnumeratedCount(Of TSource) (source As IEnumerable(Of TSource), ByRef count As Integer) As BooleanType Parameters
- TSource
The type of the elements of source.
Parameters
- source
- IEnumerable<TSource>
A sequence that contains elements to be counted.
- count
- Int32
When this method returns, contains the number of elements in source, or 0 if the count couldn't be determined without enumeration.
Returns
true if the count of source can be determined without enumeration; otherwise, false.
Remarks
The method performs a series of type tests, identifying common subtypes whose count can be determined without enumerating. This includes ICollection<T>, ICollection, and internal types used in the LINQ implementation.
The method is typically a constant-time operation, but ultimately this depends on the complexity characteristics of the underlying collection's implementation.
