通过VS2010性能分析来查找代码中那些地方最损耗资源

　　在编写完成一个程序后，大家都比较关心程序的性能如何，想把程序优化得更好。很多时候凭个人直觉来优化程序是件非常不靠普的事情，即使你是一个优秀的开人员也很难准确地判断程序中那些出现问题。VS2010提供了性能分析工具就能轻松地帮我们解决这一事情。

假设现在写了一个组件，很想知道组件和代码的性能情况。这个可以简单地写一个测试程序。

View Code

    class Program
    {
        static List<Expression> mExpressions = new List<Expression>();
        static Random mRan = new Random();
        static void Main(string[] args)
        {
            try
            {
                string dbpath = @"Data Source=d:\\northwind.db;Pooling=true;FailIfMissing=false;";
                DBContext.SetConnectionDriver<SqliteDriver>(ConnectionType.Context1);
                DBContext.SetConnectionString(ConnectionType.Context1, dbpath);
                mExpressions.Add(Order.shipCountry == "Switzerland");
                mExpressions.Add(Order.shipRegion == "RJ");
                mExpressions.Add(Order.customerID.In(Customer.customerID, Customer.country == "UK"));
                mExpressions.Add(Order.customerID.In(Customer.customerID, Customer.country == "Germany"));
                mExpressions.Add(Order.orderDate > "1997-8-5");
                mExpressions.Add(Order.orderDate < "1997-12-1");
                mExpressions.Add(Order.orderDate > "1997-5-1" & Order.orderDate<"1997-11-5");
                System.Threading.Thread thread;
                for (int i = 0; i < 10; i++)
                {
                    thread = new System.Threading.Thread(new System.Threading.ParameterizedThreadStart(Test
                        ));
                    thread.Start();
                }
                
            }
            catch (Exception e_)
            {
                Console.WriteLine(e_.Message);
            }
           
        }
        static void Test(object obj)
        {
            while (true)
            {
                Expression exp = mExpressions[mRan.Next(mExpressions.Count - 1)];
                Console.WriteLine(exp.Count<Order>());
                System.Threading.Thread.Sleep(mRan.Next(50, 5000));
            }
        }
      
    }