ConcurrentBag<T>
Class
Definition
Represents a thread-safe, unordered collection of objects.
In This Article
[System.Runtime.InteropServices.ComVisible(false)]
public class ConcurrentBag<T> : System.Collections.Concurrent.IProducerConsumerCollection<T>, System.Collections.Generic.IEnumerable<T>, System.Collections.Generic.IReadOnlyCollection<T>
Type Parameters
T
The type of the elements to be stored in the collection.
Inheritance
Attributes
Implements
Inherited Members
System.Object
Examples
The following example shows how to add and remove items from a ConcurrentBag<T> :
using System;
using System.Collections.Concurrent;
class ConcurrentBagDemo
{
// Demonstrates:
// ConcurrentBag<T>.Add()
// ConcurrentBag<T>.IsEmpty
// ConcurrentBag<T>.TryTake()
// ConcurrentBag<T>.TryPeek()
static void Main()
{
// Construct and populate the ConcurrentBag
ConcurrentBag<int> cb = new ConcurrentBag<int>();
cb.Add(1);
cb.Add(2);
cb.Add(3);
// Consume the items in the bag
int item;
while (!cb.IsEmpty)
{
if (cb.TryTake(out item))
Console.WriteLine(item);
else
Console.WriteLine("TryTake failed for non-empty bag");
}
// Bag should be empty at this point
if (cb.TryPeek(out item))
Console.WriteLine("TryPeek succeeded for empty bag!");
}
}
Imports System.Collections.Concurrent
Module ConcurrentBagDemo
' Demonstrates:
' ConcurrentBag<T>.Add()
' ConcurrentBag<T>.IsEmpty
' ConcurrentBag<T>.TryTake()
' ConcurrentBag<T>.TryPeek()
Sub Main()
' Construct and populate the ConcurrentBag
Dim cb As New ConcurrentBag(Of Integer)()
cb.Add(1)
cb.Add(2)
cb.Add(3)
' Consume the items in the bag
Dim item As Integer
While Not cb.IsEmpty
If cb.TryTake(item) Then
Console.WriteLine(item)
Else
Console.WriteLine("TryTake failed for non-empty bag")
End If
End While
' Bag should be empty at this point
If cb.TryPeek(item) Then
Console.WriteLine("TryPeek succeeded for empty bag!")
End If
End Sub
End Module
Remarks
Bags are useful for storing objects when ordering doesn't matter, and unlike sets, bags support duplicates. ConcurrentBag<T> is a thread-safe bag implementation, optimized for scenarios where the same thread will be both producing and consuming data stored in the bag.
ConcurrentBag<T> accepts null as a valid value for reference types.
For more information, see the entry FAQ: Are all of the new concurrent collections lock-free? in the Parallel Programming with .NET blog.
Constructors
Properties
Methods
Explicit Interface Implementations
Extension Methods
ToImmutableArray<TSource>(IEnumerable<TSource>)
ToImmutableDictionary<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>)
ToImmutableDictionary<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>, IEqualityComparer<TKey>)
ToImmutableDictionary<TKey,TValue>(IEnumerable<KeyValuePair<TKey,TValue>>)
ToImmutableDictionary<TKey,TValue>(IEnumerable<KeyValuePair<TKey,TValue>>, IEqualityComparer<TKey>)
ToImmutableDictionary<TKey,TValue>(IEnumerable<KeyValuePair<TKey,TValue>>, IEqualityComparer<TKey>, IEqualityComparer<TValue>)
ToImmutableDictionary<TSource,TKey,TValue>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TValue>)
ToImmutableDictionary<TSource,TKey,TValue>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TValue>, IEqualityComparer<TKey>)
ToImmutableDictionary<TSource,TKey,TValue>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TValue>, IEqualityComparer<TKey>, IEqualityComparer<TValue>)
ToImmutableHashSet<TSource>(IEnumerable<TSource>)
ToImmutableHashSet<TSource>(IEnumerable<TSource>, IEqualityComparer<TSource>)
ToImmutableList<TSource>(IEnumerable<TSource>)
ToImmutableSortedDictionary<TKey,TValue>(IEnumerable<KeyValuePair<TKey,TValue>>)
ToImmutableSortedDictionary<TKey,TValue>(IEnumerable<KeyValuePair<TKey,TValue>>, IComparer<TKey>)
ToImmutableSortedDictionary<TKey,TValue>(IEnumerable<KeyValuePair<TKey,TValue>>, IComparer<TKey>, IEqualityComparer<TValue>)
ToImmutableSortedDictionary<TSource,TKey,TValue>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TValue>)
ToImmutableSortedDictionary<TSource,TKey,TValue>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TValue>, IComparer<TKey>)
ToImmutableSortedDictionary<TSource,TKey,TValue>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TValue>, IComparer<TKey>, IEqualityComparer<TValue>)
ToImmutableSortedSet<TSource>(IEnumerable<TSource>)
ToImmutableSortedSet<TSource>(IEnumerable<TSource>, IComparer<TSource>)
CopyToDataTable<T>(IEnumerable<T>)
CopyToDataTable<T>(IEnumerable<T>, DataTable, LoadOption)
CopyToDataTable<T>(IEnumerable<T>, DataTable, LoadOption, FillErrorEventHandler)
Aggregate<TSource>(IEnumerable<TSource>, Func<TSource,TSource,TSource>)
Aggregate<TSource,TAccumulate>(IEnumerable<TSource>, TAccumulate, Func<TAccumulate,TSource,TAccumulate>)
Aggregate<TSource,TAccumulate,TResult>(IEnumerable<TSource>, TAccumulate, Func<TAccumulate,TSource,TAccumulate>, Func<TAccumulate,TResult>)
All<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)
Any<TSource>(IEnumerable<TSource>)
Any<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)
Append<TSource>(IEnumerable<TSource>, TSource)
AsEnumerable<TSource>(IEnumerable<TSource>)
Average(IEnumerable<Decimal>)
Average(IEnumerable<Double>)
Average(IEnumerable<Int32>)
Average(IEnumerable<Int64>)
Average(IEnumerable<Nullable<Decimal>>)
Average(IEnumerable<Nullable<Double>>)
Average(IEnumerable<Nullable<Int32>>)
Average(IEnumerable<Nullable<Int64>>)
Average(IEnumerable<Nullable<Single>>)
Average(IEnumerable<Single>)
Average<TSource>(IEnumerable<TSource>, Func<TSource,Decimal>)
Average<TSource>(IEnumerable<TSource>, Func<TSource,Double>)
Average<TSource>(IEnumerable<TSource>, Func<TSource,Int32>)
Average<TSource>(IEnumerable<TSource>, Func<TSource,Int64>)
Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Decimal>>)
Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Double>>)
Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int32>>)
Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int64>>)
Average<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Single>>)
Average<TSource>(IEnumerable<TSource>, Func<TSource,Single>)
Cast<TResult>(IEnumerable)
Concat<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)
Contains<TSource>(IEnumerable<TSource>, TSource)
Contains<TSource>(IEnumerable<TSource>, TSource, IEqualityComparer<TSource>)
Count<TSource>(IEnumerable<TSource>)
Count<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)
DefaultIfEmpty<TSource>(IEnumerable<TSource>)
DefaultIfEmpty<TSource>(IEnumerable<TSource>, TSource)
Distinct<TSource>(IEnumerable<TSource>)
Distinct<TSource>(IEnumerable<TSource>, IEqualityComparer<TSource>)
ElementAt<TSource>(IEnumerable<TSource>, Int32)
ElementAtOrDefault<TSource>(IEnumerable<TSource>, Int32)
Except<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)
Except<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>)
First<TSource>(IEnumerable<TSource>)
First<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)
FirstOrDefault<TSource>(IEnumerable<TSource>)
FirstOrDefault<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)
GroupBy<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>)
GroupBy<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>, IEqualityComparer<TKey>)
GroupBy<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>)
GroupBy<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>, IEqualityComparer<TKey>)
GroupBy<TSource,TKey,TResult>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TKey,IEnumerable<TSource>,TResult>)
GroupBy<TSource,TKey,TResult>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TKey,IEnumerable<TSource>,TResult>, IEqualityComparer<TKey>)
GroupBy<TSource,TKey,TElement,TResult>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>, Func<TKey,IEnumerable<TElement>,TResult>)
GroupBy<TSource,TKey,TElement,TResult>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>, Func<TKey,IEnumerable<TElement>,TResult>, IEqualityComparer<TKey>)
GroupJoin<TOuter,TInner,TKey,TResult>(IEnumerable<TOuter>, IEnumerable<TInner>, Func<TOuter,TKey>, Func<TInner,TKey>, Func<TOuter,IEnumerable<TInner>,TResult>)
GroupJoin<TOuter,TInner,TKey,TResult>(IEnumerable<TOuter>, IEnumerable<TInner>, Func<TOuter,TKey>, Func<TInner,TKey>, Func<TOuter,IEnumerable<TInner>,TResult>, IEqualityComparer<TKey>)
Intersect<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)
Intersect<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>)
Join<TOuter,TInner,TKey,TResult>(IEnumerable<TOuter>, IEnumerable<TInner>, Func<TOuter,TKey>, Func<TInner,TKey>, Func<TOuter,TInner,TResult>)
Join<TOuter,TInner,TKey,TResult>(IEnumerable<TOuter>, IEnumerable<TInner>, Func<TOuter,TKey>, Func<TInner,TKey>, Func<TOuter,TInner,TResult>, IEqualityComparer<TKey>)
Last<TSource>(IEnumerable<TSource>)
Last<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)
LastOrDefault<TSource>(IEnumerable<TSource>)
LastOrDefault<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)
LongCount<TSource>(IEnumerable<TSource>)
LongCount<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)
Max(IEnumerable<Decimal>)
Max(IEnumerable<Double>)
Max(IEnumerable<Int32>)
Max(IEnumerable<Int64>)
Max(IEnumerable<Nullable<Decimal>>)
Max(IEnumerable<Nullable<Double>>)
Max(IEnumerable<Nullable<Int32>>)
Max(IEnumerable<Nullable<Int64>>)
Max(IEnumerable<Nullable<Single>>)
Max(IEnumerable<Single>)
Max<TSource>(IEnumerable<TSource>)
Max<TSource>(IEnumerable<TSource>, Func<TSource,Decimal>)
Max<TSource>(IEnumerable<TSource>, Func<TSource,Double>)
Max<TSource>(IEnumerable<TSource>, Func<TSource,Int32>)
Max<TSource>(IEnumerable<TSource>, Func<TSource,Int64>)
Max<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Decimal>>)
Max<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Double>>)
Max<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int32>>)
Max<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int64>>)
Max<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Single>>)
Max<TSource>(IEnumerable<TSource>, Func<TSource,Single>)
Max<TSource,TResult>(IEnumerable<TSource>, Func<TSource,TResult>)
Min(IEnumerable<Decimal>)
Min(IEnumerable<Double>)
Min(IEnumerable<Int32>)
Min(IEnumerable<Int64>)
Min(IEnumerable<Nullable<Decimal>>)
Min(IEnumerable<Nullable<Double>>)
Min(IEnumerable<Nullable<Int32>>)
Min(IEnumerable<Nullable<Int64>>)
Min(IEnumerable<Nullable<Single>>)
Min(IEnumerable<Single>)
Min<TSource>(IEnumerable<TSource>)
Min<TSource>(IEnumerable<TSource>, Func<TSource,Decimal>)
Min<TSource>(IEnumerable<TSource>, Func<TSource,Double>)
Min<TSource>(IEnumerable<TSource>, Func<TSource,Int32>)
Min<TSource>(IEnumerable<TSource>, Func<TSource,Int64>)
Min<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Decimal>>)
Min<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Double>>)
Min<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int32>>)
Min<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int64>>)
Min<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Single>>)
Min<TSource>(IEnumerable<TSource>, Func<TSource,Single>)
Min<TSource,TResult>(IEnumerable<TSource>, Func<TSource,TResult>)
OfType<TResult>(IEnumerable)
OrderBy<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>)
OrderBy<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>, IComparer<TKey>)
OrderByDescending<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>)
OrderByDescending<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>, IComparer<TKey>)
Prepend<TSource>(IEnumerable<TSource>, TSource)
Reverse<TSource>(IEnumerable<TSource>)
Select<TSource,TResult>(IEnumerable<TSource>, Func<TSource,TResult>)
Select<TSource,TResult>(IEnumerable<TSource>, Func<TSource,Int32,TResult>)
SelectMany<TSource,TResult>(IEnumerable<TSource>, Func<TSource,IEnumerable<TResult>>)
SelectMany<TSource,TResult>(IEnumerable<TSource>, Func<TSource,Int32,IEnumerable<TResult>>)
SelectMany<TSource,TCollection,TResult>(IEnumerable<TSource>, Func<TSource,IEnumerable<TCollection>>, Func<TSource,TCollection,TResult>)
SelectMany<TSource,TCollection,TResult>(IEnumerable<TSource>, Func<TSource,Int32,IEnumerable<TCollection>>, Func<TSource,TCollection,TResult>)
SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)
SequenceEqual<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>)
Single<TSource>(IEnumerable<TSource>)
Single<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)
SingleOrDefault<TSource>(IEnumerable<TSource>)
SingleOrDefault<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)
Skip<TSource>(IEnumerable<TSource>, Int32)
SkipLast<TSource>(IEnumerable<TSource>, Int32)
SkipWhile<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)
SkipWhile<TSource>(IEnumerable<TSource>, Func<TSource,Int32,Boolean>)
Sum(IEnumerable<Decimal>)
Sum(IEnumerable<Double>)
Sum(IEnumerable<Int32>)
Sum(IEnumerable<Int64>)
Sum(IEnumerable<Nullable<Decimal>>)
Sum(IEnumerable<Nullable<Double>>)
Sum(IEnumerable<Nullable<Int32>>)
Sum(IEnumerable<Nullable<Int64>>)
Sum(IEnumerable<Nullable<Single>>)
Sum(IEnumerable<Single>)
Sum<TSource>(IEnumerable<TSource>, Func<TSource,Decimal>)
Sum<TSource>(IEnumerable<TSource>, Func<TSource,Double>)
Sum<TSource>(IEnumerable<TSource>, Func<TSource,Int32>)
Sum<TSource>(IEnumerable<TSource>, Func<TSource,Int64>)
Sum<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Decimal>>)
Sum<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Double>>)
Sum<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int32>>)
Sum<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Int64>>)
Sum<TSource>(IEnumerable<TSource>, Func<TSource,Nullable<Single>>)
Sum<TSource>(IEnumerable<TSource>, Func<TSource,Single>)
Take<TSource>(IEnumerable<TSource>, Int32)
TakeLast<TSource>(IEnumerable<TSource>, Int32)
TakeWhile<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)
TakeWhile<TSource>(IEnumerable<TSource>, Func<TSource,Int32,Boolean>)
ToArray<TSource>(IEnumerable<TSource>)
ToDictionary<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>)
ToDictionary<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>, IEqualityComparer<TKey>)
ToDictionary<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>)
ToDictionary<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>, IEqualityComparer<TKey>)
ToHashSet<TSource>(IEnumerable<TSource>)
ToHashSet<TSource>(IEnumerable<TSource>, IEqualityComparer<TSource>)
ToList<TSource>(IEnumerable<TSource>)
ToLookup<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>)
ToLookup<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>, IEqualityComparer<TKey>)
ToLookup<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>)
ToLookup<TSource,TKey,TElement>(IEnumerable<TSource>, Func<TSource,TKey>, Func<TSource,TElement>, IEqualityComparer<TKey>)
Union<TSource>(IEnumerable<TSource>, IEnumerable<TSource>)
Union<TSource>(IEnumerable<TSource>, IEnumerable<TSource>, IEqualityComparer<TSource>)
Where<TSource>(IEnumerable<TSource>, Func<TSource,Boolean>)
Where<TSource>(IEnumerable<TSource>, Func<TSource,Int32,Boolean>)
Zip<TFirst,TSecond,TResult>(IEnumerable<TFirst>, IEnumerable<TSecond>, Func<TFirst,TSecond,TResult>)
AsParallel(IEnumerable)
AsParallel<TSource>(IEnumerable<TSource>)
AsQueryable(IEnumerable)
AsQueryable<TElement>(IEnumerable<TElement>)
Ancestors<T>(IEnumerable<T>)
Ancestors<T>(IEnumerable<T>, XName)
AncestorsAndSelf(IEnumerable<XElement>)
AncestorsAndSelf(IEnumerable<XElement>, XName)
Attributes(IEnumerable<XElement>)
Attributes(IEnumerable<XElement>, XName)
DescendantNodes<T>(IEnumerable<T>)
DescendantNodesAndSelf(IEnumerable<XElement>)
Descendants<T>(IEnumerable<T>)
Descendants<T>(IEnumerable<T>, XName)
DescendantsAndSelf(IEnumerable<XElement>)
DescendantsAndSelf(IEnumerable<XElement>, XName)
Elements<T>(IEnumerable<T>)
Elements<T>(IEnumerable<T>, XName)
InDocumentOrder<T>(IEnumerable<T>)
Nodes<T>(IEnumerable<T>)
Remove(IEnumerable<XAttribute>)
Remove<T>(IEnumerable<T>)
Thread Safety
All public and protected members of ConcurrentBag<T> are thread-safe and may be used concurrently from multiple threads. However, members accessed through one of the interfaces the ConcurrentBag<T> implements, including extension methods, are not guaranteed to be thread safe and may need to be synchronized by the caller.