Menu
MSDN states that the enumerator returned from the dictionary does not represent a moment-in-time snapshot of the dictionary. Although it will be rarely needed in multithreaded environment, but if one wants, what is the best way to get the moment-in-time snapshot of ConcurrentDictionary?
503
To retrieve single item, ConcurrentDictionary provides TryGetValue method. We have to provide Key in the TryGetValue method. It takes the out parameter to return the value of key. TryGetValue returns true if key exists, or returns false if key does not exists in dictionary.
ConcurrentDictionary - "Good read speed even in the face of concurrency, but it's a heavyweight object to create and slower to update."
You cannot just assign a ConcurrentDictionary to a Dictionary, since ConcurrentDictionary is not a subtype of Dictionary. That's the whole point of interfaces like IDictionary: You can abstract away the desired interface ("some kind of dictionary") from the concrete implementation (concurrent/non-concurrent hashmap).
Concurrent. ConcurrentDictionary<TKey,TValue>. This collection class is a thread-safe implementation. We recommend that you use it whenever multiple threads might be attempting to access the elements concurrently.
Just call ToArray() method.
Here is a source code:
/// <summary>
/// Copies the key and value pairs stored in the <see cref="ConcurrentDictionary{TKey,TValue}"/> to a
/// new array.
/// </summary>
/// <returns>A new array containing a snapshot of key and value pairs copied from the <see
/// cref="ConcurrentDictionary{TKey,TValue}"/>.</returns>
[SuppressMessage("Microsoft.Concurrency", "CA8001", Justification = "ConcurrencyCop just doesn't know about these locks")]
public KeyValuePair<TKey, TValue>[] ToArray()
{
int locksAcquired = 0;
try
{
AcquireAllLocks(ref locksAcquired);
int count = 0;
checked
{
for (int i = 0; i < m_tables.m_locks.Length; i++)
{
count += m_tables.m_countPerLock[i];
}
}
KeyValuePair<TKey, TValue>[] array = new KeyValuePair<TKey, TValue>[count];
CopyToPairs(array, 0);
return array;
}
finally
{
ReleaseLocks(0, locksAcquired);
}
}
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
