可以为枚举定义数据类型：

enum EnumName : [byte, char, int16, int32, int64, uint16, uint32, uint64]
{
    A = 1,
    B = 2
}

下面是C#4.0中字符串类的一个新方法：

String.IsNullOrWhiteSpace(String value)

是时候了。

我最喜欢的技巧是使用空联合运算符和括号为我自动实例化集合。

private IList<Foo> _foo;

public IList<Foo> ListOfFoo 
    { get { return _foo ?? (_foo = new List<Foo>()); } }

@达科他州的大卫：

Console.WriteLine( "-".PadRight( 21, '-' ) );

我曾经这样做，直到我发现String类有一个构造函数，它允许你以更干净的方式做同样的事情：

new String('-',22);

我看不到上面的这一点——直到最近我才意识到你可以做的是从另一个构造函数调用一个构造函数：

class Example
{
    public Example(int value1)
        : this(value1, "Default Value")
    {
    }

    public Example(int value1, string value2)
    {
        m_Value1 = value1;
        m_value2 = value2;
    }

    int m_Value1;
    string m_value2;
}

我参加这个聚会迟到了，所以我的第一选择已经被接受了。但我还没看到有人提到这个宝石：

.NET Framework的并行扩展

它有类似于用Parallel.For或foreach替换Parallel.foreach

平行样品：在您看来，一秒钟可以创建多少个CLR对象？参见休耕示例：

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Threading;
using System.Threading.Tasks;

namespace ObjectInitSpeedTest
{
   class Program
   {
       //Note: don't forget to build it in Release mode.
       static void Main()
       {
           normalSpeedTest();           
           parallelSpeedTest();

           Console.ForegroundColor = ConsoleColor.White;
           Console.WriteLine("Press a key ...");
           Console.ReadKey();
       }

       private static void parallelSpeedTest()
       {
           Console.ForegroundColor = ConsoleColor.Yellow;
           Console.WriteLine("parallelSpeedTest");

           long totalObjectsCreated = 0;
           long totalElapsedTime = 0;

           var tasks = new List<Task>();
           var processorCount = Environment.ProcessorCount;

           Console.WriteLine("Running on {0} cores", processorCount);

           for (var t = 0; t < processorCount; t++)
           {
               tasks.Add(Task.Factory.StartNew(
               () =>
               {
                   const int reps = 1000000000;
                   var sp = Stopwatch.StartNew();
                   for (var j = 0; j < reps; ++j)
                   {
                       new object();
                   }
                   sp.Stop();

                   Interlocked.Add(ref totalObjectsCreated, reps);
                   Interlocked.Add(ref totalElapsedTime, sp.ElapsedMilliseconds);
               }
               ));
           }

           // let's complete all the tasks
           Task.WaitAll(tasks.ToArray());

           Console.WriteLine("Created {0:N} objects in 1 sec\n", (totalObjectsCreated / (totalElapsedTime / processorCount)) * 1000);
       }

       private static void normalSpeedTest()
       {
           Console.ForegroundColor = ConsoleColor.Green;
           Console.WriteLine("normalSpeedTest");

           const int reps = 1000000000;
           var sp = Stopwatch.StartNew();
           sp.Start();
           for (var j = 0; j < reps; ++j)
           {
               new object();
           }
           sp.Stop();

           Console.WriteLine("Created {0:N} objects in 1 sec\n", (reps / sp.ElapsedMilliseconds) * 1000);
       }
   }
}