线程安全集合 ConcurrentDictionary<TKey, TValue> 类

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);
}
}