using System;

using System.Collections.Concurrent;

​

public class Program

{

    private static ConcurrentDictionary<string, int> cErrorsPerThread = new ConcurrentDictionary<string, int>();

    public static void Main()

    {

         for (int i = 0; i < 5; i++)

         {

            Send();

         }

    }

    private static void Send()

    {

        int nCount = 0;

        cErrorsPerThread.TryGetValue("THREAD1", out nCount);

        cErrorsPerThread.AddOrUpdate("THREAD1", nCount++, (key, oldValue) => nCount++);

        Console.WriteLine(cErrorsPerThread["THREAD1"]);

    }

}