ConcurrentDictionary

string res = "";
 var concurrentDictionary = new ConcurrentDictionary<int, string>();
 var dictionary = new Dictionary<int, string>();
 dictionary.TryAdd(1, "aa");
 concurrentDictionary.TryAdd(1,"");
     var sw = new Stopwatch();
     sw.Start();
 Parallel.For(0, 1000000, i =>//Parallel使用并行循环
 {
     lock (dictionary)
     {


         dictionary[i] = new Random().Next(1000, 9999).ToString();
     }
 });
 sw.Stop();
 Console.WriteLine("加锁写入dictionary {0}", sw.Elapsed);
 //wrinting to dictionary with a lock: 00:00:00.0633939
 sw.Restart();
 Parallel.For(0, 1000000, i =>
 {
     concurrentDictionary[i] = new Random().Next(1000, 9999).ToString();
 });
     sw.Stop();
     Console.WriteLine("concurrentdictionary写入时长 : {0}", sw.Elapsed);


     sw.Restart();
 Parallel.For(0, 1000000, i =>
 {
     lock (dictionary)
     {
         res = dictionary[i];
     }
 });
 sw.Stop();
 Console.WriteLine("读取dictionary耗时: {0}", sw.Elapsed);
 sw.Restart();
 Parallel.For(0, 1000000, i =>
 {
     res = concurrentDictionary[i];
 });
 sw.Stop();
 Console.WriteLine("读取concurrentdictionary耗时: {0}", sw.Elapsed);
 Console.ReadLine();