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Enumerable.Count<TSource> Method (IEnumerable<TSource>)

Returns the number of elements in a sequence.

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

public static int Count<TSource>(
	this IEnumerable<TSource> source

Type Parameters


The type of the elements of source.


Type: System.Collections.Generic.IEnumerable<TSource>
A sequence that contains elements to be counted.

Return Value

Type: System.Int32
The number of elements in the input sequence.

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.


source is null.


The number of elements in source is larger than MaxValue.

If the type of source implements ICollection<T>, that implementation is used to obtain the count of elements. Otherwise, this method determines the count.

Use the LongCount method when you expect and want to allow the result to be greater than MaxValue.

In Visual Basic query expression syntax, an Aggregate Into Count() clause translates to an invocation of Enumerable.Count.

The following code example demonstrates how to use Count<TSource>(IEnumerable<TSource>) to count the elements in an array.

      string[] fruits = { "apple", "banana", "mango", "orange", "passionfruit", "grape" };

         int numberOfFruits = fruits.Count();
         outputBlock.Text += String.Format(
             "There are {0} fruits in the collection.",
             numberOfFruits) + "\n";

      catch (OverflowException)
         outputBlock.Text += "The count is too large to store as an Int32." + "\n";
         outputBlock.Text += "Try using the LongCount() method instead." + "\n";

      // This code produces the following output:
      // There are 6 fruits in the collection. 

Windows Phone OS

Supported in: 8.1, 8.0, 7.1, 7.0

Windows Phone

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