Enumerable.Count(TSource) Method (IEnumerable(TSource), Func(TSource, Boolean))
Returns a number that represents how many elements in the specified sequence satisfy a condition.
Assemblies: System.Linq (in System.Linq.dll)
System.Core (in System.Core.dll)
static member Count : source:IEnumerable<'TSource> * predicate:Func<'TSource, bool> -> int
The type of the elements of source.
- Type: System.Collections.Generic.IEnumerable()
A sequence that contains elements to be tested and counted.
Return ValueType: System.Int32
A number that represents how many elements in the sequence satisfy the condition in the predicate function.
Usage NoteIn Visual Basic and C#, you can call this method as an instance method on any object of type IEnumerable(). 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).
If the type of source implements ICollection(T), that implementation is used to obtain the count of elements. Otherwise, this method determines the count.
In Visual Basic query expression syntax, an Aggregate Into Count() clause translates to an invocation of Count.
.NET FrameworkSupported in: 4.6, 4, 3.5
.NET Framework Client ProfileSupported in: 4, 3.5 SP1
Portable Class LibrarySupported in: Portable Class Library
.NET for Windows Store appsSupported in: Windows 8
Supported in: Windows Phone 8.1
Supported in: Windows Phone Silverlight 8.1
Supported in: Windows Phone Silverlight 8
Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.