ConcurrentDictionary<TKey,TValue> ConcurrentDictionary<TKey,TValue> ConcurrentDictionary<TKey,TValue> ConcurrentDictionary<TKey,TValue> Class

Definition

Represents a thread-safe collection of key/value pairs that can be accessed by multiple threads concurrently.

generic <typename TKey, typename TValue>
public ref class ConcurrentDictionary : System::Collections::Generic::ICollection<System::Collections::Generic::KeyValuePair<TKey, TValue>>, System::Collections::Generic::IDictionary<TKey, TValue>, System::Collections::Generic::IEnumerable<System::Collections::Generic::KeyValuePair<TKey, TValue>>, System::Collections::Generic::IReadOnlyCollection<System::Collections::Generic::KeyValuePair<TKey, TValue>>, System::Collections::Generic::IReadOnlyDictionary<TKey, TValue>, System::Collections::IDictionary
[System.Runtime.InteropServices.ComVisible(false)]
[System.Serializable]
public class ConcurrentDictionary<TKey,TValue> : System.Collections.Generic.ICollection<System.Collections.Generic.KeyValuePair<TKey,TValue>>, System.Collections.Generic.IDictionary<TKey,TValue>, System.Collections.Generic.IEnumerable<System.Collections.Generic.KeyValuePair<TKey,TValue>>, System.Collections.Generic.IReadOnlyCollection<System.Collections.Generic.KeyValuePair<TKey,TValue>>, System.Collections.Generic.IReadOnlyDictionary<TKey,TValue>, System.Collections.IDictionary
type ConcurrentDictionary<'Key, 'Value> = class
    interface IDictionary<'Key, 'Value>
    interface IDictionary
    interface IReadOnlyDictionary<'Key, 'Value>
    interface ICollection<KeyValuePair<'Key, 'Value>>
    interface seq<KeyValuePair<'Key, 'Value>>
    interface IEnumerable
    interface ICollection
    interface IReadOnlyCollection<KeyValuePair<'Key, 'Value>>
Public Class ConcurrentDictionary(Of TKey, TValue)
Implements ICollection(Of KeyValuePair(Of TKey, TValue)), IDictionary, IDictionary(Of TKey, TValue), IEnumerable(Of KeyValuePair(Of TKey, TValue)), IReadOnlyCollection(Of KeyValuePair(Of TKey, TValue)), IReadOnlyDictionary(Of TKey, TValue)

Type Parameters

TKey

The type of the keys in the dictionary.

TValue

The type of the values in the dictionary.

Inheritance
ConcurrentDictionary<TKey,TValue>ConcurrentDictionary<TKey,TValue>ConcurrentDictionary<TKey,TValue>ConcurrentDictionary<TKey,TValue>
Attributes
Implements

Examples

The following example shows how to construct a ConcurrentDictionary<TKey,TValue> object.


class CD_Ctor
{
        // Demonstrates:
        //      ConcurrentDictionary<TKey, TValue> ctor(concurrencyLevel, initialCapacity)
        //      ConcurrentDictionary<TKey, TValue>[TKey]
        static void Main()
        {
            // We know how many items we want to insert into the ConcurrentDictionary.
            // So set the initial capacity to some prime number above that, to ensure that
            // the ConcurrentDictionary does not need to be resized while initializing it.
            int NUMITEMS = 64;
            int initialCapacity = 101;

            // The higher the concurrencyLevel, the higher the theoretical number of operations
            // that could be performed concurrently on the ConcurrentDictionary.  However, global
            // operations like resizing the dictionary take longer as the concurrencyLevel rises. 
            // For the purposes of this example, we'll compromise at numCores * 2.
            int numProcs = Environment.ProcessorCount;
            int concurrencyLevel = numProcs * 2;

            // Construct the dictionary with the desired concurrencyLevel and initialCapacity
            ConcurrentDictionary<int, int> cd = new ConcurrentDictionary<int, int>(concurrencyLevel, initialCapacity);

            // Initialize the dictionary
            for (int i = 0; i < NUMITEMS; i++) cd[i] = i * i;

            Console.WriteLine("The square of 23 is {0} (should be {1})", cd[23], 23 * 23);
        }
}
Imports System.Collections.Concurrent
Imports System.Threading.Tasks
Class CD_Ctor
    ' Demonstrates:
    ' ConcurrentDictionary<TKey, TValue> ctor(concurrencyLevel, initialCapacity)
    ' ConcurrentDictionary<TKey, TValue>[TKey]
    Shared Sub Main()
        ' We know how many items we want to insert into the ConcurrentDictionary.
        ' So set the initial capacity to some prime number above that, to ensure that
        ' the ConcurrentDictionary does not need to be resized while initializing it.
        Dim NUMITEMS As Integer = 64
        Dim initialCapacity As Integer = 101

        ' The higher the concurrencyLevel, the higher the theoretical number of operations
        ' that could be performed concurrently on the ConcurrentDictionary. However, global
        ' operations like resizing the dictionary take longer as the concurrencyLevel rises. 
        ' For the purposes of this example, we'll compromise at numCores * 2.
        Dim numProcs As Integer = Environment.ProcessorCount
        Dim concurrencyLevel As Integer = numProcs * 2

        ' Construct the dictionary with the desired concurrencyLevel and initialCapacity
        Dim cd As New ConcurrentDictionary(Of Integer, Integer)(concurrencyLevel, initialCapacity)

        ' Initialize the dictionary
        For i As Integer = 0 To NUMITEMS - 1
            cd(i) = i * i
        Next

        Console.WriteLine("The square of 23 is {0} (should be {1})", cd(23), 23 * 23)
    End Sub
End Class

Remarks

For very large ConcurrentDictionary<TKey,TValue> objects, you can increase the maximum array size to 2 gigabytes (GB) on a 64-bit system by setting the <gcAllowVeryLargeObjects> configuration element to true in the run-time environment.

Note

ConcurrentDictionary<TKey,TValue> implements the IReadOnlyCollection<T> and IReadOnlyDictionary<TKey,TValue> interfaces starting with the .NET Framework 4.6; in previous versions of the .NET Framework, the ConcurrentDictionary<TKey,TValue> class did not implement these interfaces.

Like the System.Collections.Generic.Dictionary<TKey,TValue> class, ConcurrentDictionary<TKey,TValue> implements the IDictionary<TKey,TValue> interface. In addition, ConcurrentDictionary<TKey,TValue> provides several methods for adding or updating key/value pairs in the dictionary, as described in the following table.

To do this Use this method Usage notes
Add a new key to the dictionary, if it doesn't already exist in the dictionary TryAdd This method adds the specified key/value pair, if the key doesn't currently exist in the dictionary. The method returns true or false depending on whether the new pair was added.
Update the value for an existing key in the dictionary, if that key has a specific value TryUpdate This method checks whether the key has a specified value, and if it does, updates the key with a new value. It's similar to the CompareExchange method, except that it's used for dictionary elements.
Store a key/value pair in the dictionary unconditionally, and overwrite the value of a key that already exists The indexer's setter: dictionary[key] = newValue
Add a key/value pair to the dictionary, or if the key already exists, update the value for the key based on the key's existing value AddOrUpdate(TKey, Func<TKey,TValue>, Func<TKey,TValue,TValue>)

-or-

AddOrUpdate(TKey, TValue, Func<TKey,TValue,TValue>)
AddOrUpdate(TKey, Func<TKey,TValue>, Func<TKey,TValue,TValue>) accepts the key and two delegates. It uses the first delegate if the key doesn't exist in the dictionary; it accepts the key and returns the value that should be added for the key. It uses the second delegate if the key does exist; it accepts the key and its current value, and it returns the new value that should be set for the key.

AddOrUpdate(TKey, TValue, Func<TKey,TValue,TValue>) accepts the key, a value to add, and the update delegate. This is the same as the previous overload, except that it doesn't use a delegate to add a key.
Get the value for a key in the dictionary, adding the value to the dictionary and returning it if the key doesn't exist GetOrAdd(TKey, TValue)

-or-

GetOrAdd(TKey, Func<TKey,TValue>)
These overloads provide lazy initialization for a key/value pair in the dictionary, adding the value only if it's not there.

GetOrAdd(TKey, TValue) takes the value to be added if the key doesn't exist.

GetOrAdd(TKey, Func<TKey,TValue>) takes a delegate that will generate the value if the key doesn't exist.

All these operations are atomic and are thread-safe with regards to all other operations on the ConcurrentDictionary<TKey,TValue> class. The only exceptions are the methods that accept a delegate, that is, AddOrUpdate and GetOrAdd. For modifications and write operations to the dictionary, ConcurrentDictionary<TKey,TValue> uses fine-grained locking to ensure thread safety. (Read operations on the dictionary are performed in a lock-free manner.) However, delegates for these methods are called outside the locks to avoid the problems that can arise from executing unknown code under a lock. Therefore, the code executed by these delegates is not subject to the atomicity of the operation.

Constructors

ConcurrentDictionary<TKey,TValue>() ConcurrentDictionary<TKey,TValue>() ConcurrentDictionary<TKey,TValue>() ConcurrentDictionary<TKey,TValue>()

Initializes a new instance of the ConcurrentDictionary<TKey,TValue> class that is empty, has the default concurrency level, has the default initial capacity, and uses the default comparer for the key type.

ConcurrentDictionary<TKey,TValue>(IEnumerable<KeyValuePair<TKey,TValue>>) ConcurrentDictionary<TKey,TValue>(IEnumerable<KeyValuePair<TKey,TValue>>) ConcurrentDictionary<TKey,TValue>(IEnumerable<KeyValuePair<TKey,TValue>>) ConcurrentDictionary<TKey,TValue>(IEnumerable<KeyValuePair<TKey,TValue>>)

Initializes a new instance of the ConcurrentDictionary<TKey,TValue> class that contains elements copied from the specified IEnumerable<T>, has the default concurrency level, has the default initial capacity, and uses the default comparer for the key type.

ConcurrentDictionary<TKey,TValue>(IEnumerable<KeyValuePair<TKey,TValue>>, IEqualityComparer<TKey>) ConcurrentDictionary<TKey,TValue>(IEnumerable<KeyValuePair<TKey,TValue>>, IEqualityComparer<TKey>) ConcurrentDictionary<TKey,TValue>(IEnumerable<KeyValuePair<TKey,TValue>>, IEqualityComparer<TKey>) ConcurrentDictionary<TKey,TValue>(IEnumerable<KeyValuePair<TKey,TValue>>, IEqualityComparer<TKey>)

Initializes a new instance of the ConcurrentDictionary<TKey,TValue> class that contains elements copied from the specified IEnumerable has the default concurrency level, has the default initial capacity, and uses the specified IEqualityComparer<T>.

ConcurrentDictionary<TKey,TValue>(IEqualityComparer<TKey>) ConcurrentDictionary<TKey,TValue>(IEqualityComparer<TKey>) ConcurrentDictionary<TKey,TValue>(IEqualityComparer<TKey>) ConcurrentDictionary<TKey,TValue>(IEqualityComparer<TKey>)

Initializes a new instance of the ConcurrentDictionary<TKey,TValue> class that is empty, has the default concurrency level and capacity, and uses the specified IEqualityComparer<T>.

ConcurrentDictionary<TKey,TValue>(Int32, IEnumerable<KeyValuePair<TKey,TValue>>, IEqualityComparer<TKey>) ConcurrentDictionary<TKey,TValue>(Int32, IEnumerable<KeyValuePair<TKey,TValue>>, IEqualityComparer<TKey>) ConcurrentDictionary<TKey,TValue>(Int32, IEnumerable<KeyValuePair<TKey,TValue>>, IEqualityComparer<TKey>) ConcurrentDictionary<TKey,TValue>(Int32, IEnumerable<KeyValuePair<TKey,TValue>>, IEqualityComparer<TKey>)

Initializes a new instance of the ConcurrentDictionary<TKey,TValue> class that contains elements copied from the specified IEnumerable, and uses the specified IEqualityComparer<T>.

ConcurrentDictionary<TKey,TValue>(Int32, Int32) ConcurrentDictionary<TKey,TValue>(Int32, Int32) ConcurrentDictionary<TKey,TValue>(Int32, Int32) ConcurrentDictionary<TKey,TValue>(Int32, Int32)

Initializes a new instance of the ConcurrentDictionary<TKey,TValue> class that is empty, has the specified concurrency level and capacity, and uses the default comparer for the key type.

ConcurrentDictionary<TKey,TValue>(Int32, Int32, IEqualityComparer<TKey>) ConcurrentDictionary<TKey,TValue>(Int32, Int32, IEqualityComparer<TKey>) ConcurrentDictionary<TKey,TValue>(Int32, Int32, IEqualityComparer<TKey>) ConcurrentDictionary<TKey,TValue>(Int32, Int32, IEqualityComparer<TKey>)

Initializes a new instance of the ConcurrentDictionary<TKey,TValue> class that is empty, has the specified concurrency level, has the specified initial capacity, and uses the specified IEqualityComparer<T>.

Properties

Count Count Count Count

Gets the number of key/value pairs contained in the ConcurrentDictionary<TKey,TValue>.

IsEmpty IsEmpty IsEmpty IsEmpty

Gets a value that indicates whether the ConcurrentDictionary<TKey,TValue> is empty.

Item[TKey] Item[TKey] Item[TKey] Item[TKey]

Gets or sets the value associated with the specified key.

Keys Keys Keys Keys

Gets a collection containing the keys in the Dictionary<TKey,TValue>.

Values Values Values Values

Gets a collection that contains the values in the Dictionary<TKey,TValue>.

Methods

AddOrUpdate(TKey, Func<TKey,TValue>, Func<TKey,TValue,TValue>) AddOrUpdate(TKey, Func<TKey,TValue>, Func<TKey,TValue,TValue>) AddOrUpdate(TKey, Func<TKey,TValue>, Func<TKey,TValue,TValue>) AddOrUpdate(TKey, Func<TKey,TValue>, Func<TKey,TValue,TValue>)

Uses the specified functions to add a key/value pair to the ConcurrentDictionary<TKey,TValue> if the key does not already exist, or to update a key/value pair in the ConcurrentDictionary<TKey,TValue> if the key already exists.

AddOrUpdate(TKey, TValue, Func<TKey,TValue,TValue>) AddOrUpdate(TKey, TValue, Func<TKey,TValue,TValue>) AddOrUpdate(TKey, TValue, Func<TKey,TValue,TValue>) AddOrUpdate(TKey, TValue, Func<TKey,TValue,TValue>)

Adds a key/value pair to the ConcurrentDictionary<TKey,TValue> if the key does not already exist, or updates a key/value pair in the ConcurrentDictionary<TKey,TValue> by using the specified function if the key already exists.

AddOrUpdate<TArg>(TKey, Func<TKey,TArg,TValue>, Func<TKey,TValue,TArg,TValue>, TArg) AddOrUpdate<TArg>(TKey, Func<TKey,TArg,TValue>, Func<TKey,TValue,TArg,TValue>, TArg) AddOrUpdate<TArg>(TKey, Func<TKey,TArg,TValue>, Func<TKey,TValue,TArg,TValue>, TArg) AddOrUpdate<TArg>(TKey, Func<TKey,TArg,TValue>, Func<TKey,TValue,TArg,TValue>, TArg)

Uses the specified functions and argument to add a key/value pair to the ConcurrentDictionary<TKey,TValue> if the key does not already exist, or to update a key/value pair in the ConcurrentDictionary<TKey,TValue> if the key already exists.

Clear() Clear() Clear() Clear()

Removes all keys and values from the ConcurrentDictionary<TKey,TValue>.

ContainsKey(TKey) ContainsKey(TKey) ContainsKey(TKey) ContainsKey(TKey)

Determines whether the ConcurrentDictionary<TKey,TValue> contains the specified key.

Equals(Object) Equals(Object) Equals(Object) Equals(Object)

Determines whether the specified object is equal to the current object.

(Inherited from Object)
GetEnumerator() GetEnumerator() GetEnumerator() GetEnumerator()

Returns an enumerator that iterates through the ConcurrentDictionary<TKey,TValue>.

GetHashCode() GetHashCode() GetHashCode() GetHashCode()

Serves as the default hash function.

(Inherited from Object)
GetOrAdd(TKey, Func<TKey,TValue>) GetOrAdd(TKey, Func<TKey,TValue>) GetOrAdd(TKey, Func<TKey,TValue>) GetOrAdd(TKey, Func<TKey,TValue>)

Adds a key/value pair to the ConcurrentDictionary<TKey,TValue> by using the specified function if the key does not already exist. Returns the new value, or the existing value if the key exists.

GetOrAdd(TKey, TValue) GetOrAdd(TKey, TValue) GetOrAdd(TKey, TValue) GetOrAdd(TKey, TValue)

Adds a key/value pair to the ConcurrentDictionary<TKey,TValue> if the key does not already exist. Returns the new value, or the existing value if the key exists.

GetOrAdd<TArg>(TKey, Func<TKey,TArg,TValue>, TArg) GetOrAdd<TArg>(TKey, Func<TKey,TArg,TValue>, TArg) GetOrAdd<TArg>(TKey, Func<TKey,TArg,TValue>, TArg) GetOrAdd<TArg>(TKey, Func<TKey,TArg,TValue>, TArg)

Adds a key/value pair to the ConcurrentDictionary<TKey,TValue> by using the specified function and an argument if the key does not already exist, or returns the existing value if the key exists.

GetType() GetType() GetType() GetType()

Gets the Type of the current instance.

(Inherited from Object)
MemberwiseClone() MemberwiseClone() MemberwiseClone() MemberwiseClone()

Creates a shallow copy of the current Object.

(Inherited from Object)
ToArray() ToArray() ToArray() ToArray()

Copies the key and value pairs stored in the ConcurrentDictionary<TKey,TValue> to a new array.

ToString() ToString() ToString() ToString()

Returns a string that represents the current object.

(Inherited from Object)
TryAdd(TKey, TValue) TryAdd(TKey, TValue) TryAdd(TKey, TValue) TryAdd(TKey, TValue)

Attempts to add the specified key and value to the ConcurrentDictionary<TKey,TValue>.

TryGetValue(TKey, TValue) TryGetValue(TKey, TValue) TryGetValue(TKey, TValue) TryGetValue(TKey, TValue)

Attempts to get the value associated with the specified key from the ConcurrentDictionary<TKey,TValue>.

TryRemove(TKey, TValue) TryRemove(TKey, TValue) TryRemove(TKey, TValue) TryRemove(TKey, TValue)

Attempts to remove and return the value that has the specified key from the ConcurrentDictionary<TKey,TValue>.

TryUpdate(TKey, TValue, TValue) TryUpdate(TKey, TValue, TValue) TryUpdate(TKey, TValue, TValue) TryUpdate(TKey, TValue, TValue)

Updates the value associated with key to newValue if the existing value with key is equal to comparisonValue.

Explicit Interface Implementations

ICollection.CopyTo(Array, Int32) ICollection.CopyTo(Array, Int32) ICollection.CopyTo(Array, Int32) ICollection.CopyTo(Array, Int32)

Copies the elements of the ICollection to an array, starting at the specified array index.

ICollection.IsSynchronized ICollection.IsSynchronized ICollection.IsSynchronized ICollection.IsSynchronized

Gets a value that indicates whether access to the ICollection is synchronized with the SyncRoot.

ICollection.SyncRoot ICollection.SyncRoot ICollection.SyncRoot ICollection.SyncRoot

Gets an object that can be used to synchronize access to the ICollection. This property is not supported.

ICollection<KeyValuePair<TKey,TValue>>.Add(KeyValuePair<TKey,TValue>) ICollection<KeyValuePair<TKey,TValue>>.Add(KeyValuePair<TKey,TValue>) ICollection<KeyValuePair<TKey,TValue>>.Add(KeyValuePair<TKey,TValue>) ICollection<KeyValuePair<TKey,TValue>>.Add(KeyValuePair<TKey,TValue>)

Adds an item to the collection.

ICollection<KeyValuePair<TKey,TValue>>.Contains(KeyValuePair<TKey,TValue>) ICollection<KeyValuePair<TKey,TValue>>.Contains(KeyValuePair<TKey,TValue>) ICollection<KeyValuePair<TKey,TValue>>.Contains(KeyValuePair<TKey,TValue>) ICollection<KeyValuePair<TKey,TValue>>.Contains(KeyValuePair<TKey,TValue>)

Gets whether the ICollection<T> contains an element with the specified key.

ICollection<KeyValuePair<TKey,TValue>>.CopyTo(KeyValuePair<TKey,TValue>[], Int32) ICollection<KeyValuePair<TKey,TValue>>.CopyTo(KeyValuePair<TKey,TValue>[], Int32) ICollection<KeyValuePair<TKey,TValue>>.CopyTo(KeyValuePair<TKey,TValue>[], Int32) ICollection<KeyValuePair<TKey,TValue>>.CopyTo(KeyValuePair<TKey,TValue>[], Int32)

Copies the elements of the ICollection to an array, starting at the specified array index.

ICollection<KeyValuePair<TKey,TValue>>.IsReadOnly ICollection<KeyValuePair<TKey,TValue>>.IsReadOnly ICollection<KeyValuePair<TKey,TValue>>.IsReadOnly ICollection<KeyValuePair<TKey,TValue>>.IsReadOnly

Gets a value that indicates whether the ICollection is read-only.

ICollection<KeyValuePair<TKey,TValue>>.Remove(KeyValuePair<TKey,TValue>) ICollection<KeyValuePair<TKey,TValue>>.Remove(KeyValuePair<TKey,TValue>) ICollection<KeyValuePair<TKey,TValue>>.Remove(KeyValuePair<TKey,TValue>) ICollection<KeyValuePair<TKey,TValue>>.Remove(KeyValuePair<TKey,TValue>)

Removes the specified key/value pair from the collection.

IDictionary.Add(Object, Object) IDictionary.Add(Object, Object) IDictionary.Add(Object, Object) IDictionary.Add(Object, Object)

Adds the specified key and value to the dictionary.

IDictionary.Contains(Object) IDictionary.Contains(Object) IDictionary.Contains(Object) IDictionary.Contains(Object)

Gets a value that indicates the IDictionary<TKey,TValue> contains an element with the specified key.

IDictionary.GetEnumerator() IDictionary.GetEnumerator() IDictionary.GetEnumerator() IDictionary.GetEnumerator()

Provides a IDictionaryEnumerator for the IDictionary<TKey,TValue>.

IDictionary.IsFixedSize IDictionary.IsFixedSize IDictionary.IsFixedSize IDictionary.IsFixedSize

Gets a value that indicates whether the IDictionary<TKey,TValue> has a fixed size.

IDictionary.IsReadOnly IDictionary.IsReadOnly IDictionary.IsReadOnly IDictionary.IsReadOnly

Gets a value that indicates whether the IDictionary<TKey,TValue> is read-only.

IDictionary.Item[Object] IDictionary.Item[Object] IDictionary.Item[Object] IDictionary.Item[Object]

Gets or sets the value associated with the specified key.

IDictionary.Keys IDictionary.Keys IDictionary.Keys IDictionary.Keys

Gets an ICollection that contains the keys of the IDictionary<TKey,TValue>.

IDictionary.Remove(Object) IDictionary.Remove(Object) IDictionary.Remove(Object) IDictionary.Remove(Object)

Removes the element with the specified key from the IDictionary.

IDictionary.Values IDictionary.Values IDictionary.Values IDictionary.Values

Gets an ICollection that contains the values in the IDictionary.

IDictionary<TKey,TValue>.Add(TKey, TValue) IDictionary<TKey,TValue>.Add(TKey, TValue) IDictionary<TKey,TValue>.Add(TKey, TValue) IDictionary<TKey,TValue>.Add(TKey, TValue)

Adds the specified key and value to the IDictionary<TKey,TValue>.

IDictionary<TKey,TValue>.Remove(TKey) IDictionary<TKey,TValue>.Remove(TKey) IDictionary<TKey,TValue>.Remove(TKey) IDictionary<TKey,TValue>.Remove(TKey)

Removes the element with the specified key from the IDictionary<TKey,TValue>.

IEnumerable.GetEnumerator() IEnumerable.GetEnumerator() IEnumerable.GetEnumerator() IEnumerable.GetEnumerator()

Returns an enumerator that iterates through the ConcurrentDictionary<TKey,TValue>.

IReadOnlyDictionary<TKey,TValue>.Keys IReadOnlyDictionary<TKey,TValue>.Keys IReadOnlyDictionary<TKey,TValue>.Keys IReadOnlyDictionary<TKey,TValue>.Keys

Gets a collection containing the keys in the Dictionary<TKey,TValue>.

IReadOnlyDictionary<TKey,TValue>.Values IReadOnlyDictionary<TKey,TValue>.Values IReadOnlyDictionary<TKey,TValue>.Values IReadOnlyDictionary<TKey,TValue>.Values

Gets a collection that contains the values in the Dictionary<TKey,TValue>.

Extension Methods

GetValueOrDefault<TKey,TValue>(IReadOnlyDictionary<TKey,TValue>, TKey) GetValueOrDefault<TKey,TValue>(IReadOnlyDictionary<TKey,TValue>, TKey) GetValueOrDefault<TKey,TValue>(IReadOnlyDictionary<TKey,TValue>, TKey) GetValueOrDefault<TKey,TValue>(IReadOnlyDictionary<TKey,TValue>, TKey)
GetValueOrDefault<TKey,TValue>(IReadOnlyDictionary<TKey,TValue>, TKey, TValue) GetValueOrDefault<TKey,TValue>(IReadOnlyDictionary<TKey,TValue>, TKey, TValue) GetValueOrDefault<TKey,TValue>(IReadOnlyDictionary<TKey,TValue>, TKey, TValue) GetValueOrDefault<TKey,TValue>(IReadOnlyDictionary<TKey,TValue>, TKey, TValue)
Remove<TKey,TValue>(IDictionary<TKey,TValue>, TKey, TValue) Remove<TKey,TValue>(IDictionary<TKey,TValue>, TKey, TValue) Remove<TKey,TValue>(IDictionary<TKey,TValue>, TKey, TValue) Remove<TKey,TValue>(IDictionary<TKey,TValue>, TKey, TValue)
TryAdd<TKey,TValue>(IDictionary<TKey,TValue>, TKey, TValue) TryAdd<TKey,TValue>(IDictionary<TKey,TValue>, TKey, TValue) TryAdd<TKey,TValue>(IDictionary<TKey,TValue>, TKey, TValue) TryAdd<TKey,TValue>(IDictionary<TKey,TValue>, TKey, TValue)
CopyToDataTable<T>(IEnumerable<T>) CopyToDataTable<T>(IEnumerable<T>) CopyToDataTable<T>(IEnumerable<T>) CopyToDataTable<T>(IEnumerable<T>)

Returns a DataTable that contains copies of the DataRow objects, given an input IEnumerable<T> object where the generic parameter T is DataRow.

CopyToDataTable<T>(IEnumerable<T>, DataTable, LoadOption) CopyToDataTable<T>(IEnumerable<T>, DataTable, LoadOption) CopyToDataTable<T>(IEnumerable<T>, DataTable, LoadOption) CopyToDataTable<T>(IEnumerable<T>, DataTable, LoadOption)

Copies DataRow objects to the specified DataTable, given an input IEnumerable<T> object where the generic parameter T is DataRow.

CopyToDataTable<T>(IEnumerable<T>, DataTable, LoadOption, FillErrorEventHandler) CopyToDataTable<T>(IEnumerable<T>, DataTable, LoadOption, FillErrorEventHandler) CopyToDataTable<T>(IEnumerable<T>, DataTable, LoadOption, FillErrorEventHandler) CopyToDataTable<T>(IEnumerable<T>, DataTable, LoadOption, FillErrorEventHandler)

Copies DataRow objects to the specified DataTable, given an input IEnumerable<T> object where the generic parameter T is DataRow.

Cast<TResult>(IEnumerable) Cast<TResult>(IEnumerable) Cast<TResult>(IEnumerable) Cast<TResult>(IEnumerable)

Casts the elements of an IEnumerable to the specified type.

OfType<TResult>(IEnumerable) OfType<TResult>(IEnumerable) OfType<TResult>(IEnumerable) OfType<TResult>(IEnumerable)

Filters the elements of an IEnumerable based on a specified type.

AsParallel(IEnumerable) AsParallel(IEnumerable) AsParallel(IEnumerable) AsParallel(IEnumerable)

Enables parallelization of a query.

AsQueryable(IEnumerable) AsQueryable(IEnumerable) AsQueryable(IEnumerable) AsQueryable(IEnumerable)

Converts an IEnumerable to an IQueryable.

Ancestors<T>(IEnumerable<T>) Ancestors<T>(IEnumerable<T>) Ancestors<T>(IEnumerable<T>) Ancestors<T>(IEnumerable<T>)

Returns a collection of elements that contains the ancestors of every node in the source collection.

Ancestors<T>(IEnumerable<T>, XName) Ancestors<T>(IEnumerable<T>, XName) Ancestors<T>(IEnumerable<T>, XName) Ancestors<T>(IEnumerable<T>, XName)

Returns a filtered collection of elements that contains the ancestors of every node in the source collection. Only elements that have a matching XName are included in the collection.

DescendantNodes<T>(IEnumerable<T>) DescendantNodes<T>(IEnumerable<T>) DescendantNodes<T>(IEnumerable<T>) DescendantNodes<T>(IEnumerable<T>)

Returns a collection of the descendant nodes of every document and element in the source collection.

Descendants<T>(IEnumerable<T>) Descendants<T>(IEnumerable<T>) Descendants<T>(IEnumerable<T>) Descendants<T>(IEnumerable<T>)

Returns a collection of elements that contains the descendant elements of every element and document in the source collection.

Descendants<T>(IEnumerable<T>, XName) Descendants<T>(IEnumerable<T>, XName) Descendants<T>(IEnumerable<T>, XName) Descendants<T>(IEnumerable<T>, XName)

Returns a filtered collection of elements that contains the descendant elements of every element and document in the source collection. Only elements that have a matching XName are included in the collection.

Elements<T>(IEnumerable<T>) Elements<T>(IEnumerable<T>) Elements<T>(IEnumerable<T>) Elements<T>(IEnumerable<T>)

Returns a collection of the child elements of every element and document in the source collection.

Elements<T>(IEnumerable<T>, XName) Elements<T>(IEnumerable<T>, XName) Elements<T>(IEnumerable<T>, XName) Elements<T>(IEnumerable<T>, XName)

Returns a filtered collection of the child elements of every element and document in the source collection. Only elements that have a matching XName are included in the collection.

InDocumentOrder<T>(IEnumerable<T>) InDocumentOrder<T>(IEnumerable<T>) InDocumentOrder<T>(IEnumerable<T>) InDocumentOrder<T>(IEnumerable<T>)

Returns a collection of nodes that contains all nodes in the source collection, sorted in document order.

Nodes<T>(IEnumerable<T>) Nodes<T>(IEnumerable<T>) Nodes<T>(IEnumerable<T>) Nodes<T>(IEnumerable<T>)

Returns a collection of the child nodes of every document and element in the source collection.

Remove<T>(IEnumerable<T>) Remove<T>(IEnumerable<T>) Remove<T>(IEnumerable<T>) Remove<T>(IEnumerable<T>)

Removes every node in the source collection from its parent node.

Applies to

Thread Safety

All public and protected members of ConcurrentDictionary<TKey,TValue> are thread-safe and may be used concurrently from multiple threads. However, members accessed through one of the interfaces the ConcurrentDictionary<TKey,TValue> implements, including extension methods, are not guaranteed to be thread safe and may need to be synchronized by the caller.

See also