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using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ParallelLinq
{
    //博文推荐
    //https://www.codeproject.com/articles/156980/parallelism-in-net-plinq
    class Program
    {
        static void Main(string[] args)
        {
            var customers = new[] {
                new Customer { ID = 1,  FirstName = "Sandeep"  , LastName = "Ramani" },
                new Customer { ID = 2,  FirstName = "Dharmik"  , LastName = "Chotaliya" },
                new Customer { ID = 3,  FirstName = "Nisar"    ,  LastName = "Kalia" } ,
                new Customer { ID = 4,  FirstName = "Ravi"     , LastName = "Mapara" } ,
                new Customer { ID = 5,  FirstName = "Hardik"   , LastName = "Mistry" },
                new Customer { ID = 6,  FirstName = "Sandy"    , LastName = "Ramani" },
                new Customer { ID = 7,  FirstName = "Jigar"    , LastName = "Shah" },
                new Customer { ID = 8,  FirstName = "Kaushal"  , LastName = "Parik" } ,
                new Customer { ID = 9,  FirstName = "Abhishek" , LastName = "Swarnker" } ,
                new Customer { ID = 10, FirstName = "Sanket"   , LastName = "Patel" },
                new Customer { ID = 11, FirstName = "Dinesh"   , LastName = "Prajapati" },
                new Customer { ID = 12, FirstName = "Jayesh"   , LastName = "Patel" },
                new Customer { ID = 13, FirstName = "Nimesh"   , LastName = "Mishra" } ,
                new Customer { ID = 14, FirstName = "Shiva"    , LastName = "Reddy" } ,
                new Customer { ID = 15, FirstName = "Jasmin"   , LastName = "Malviya" },
                new Customer { ID = 16, FirstName = "Haresh"   , LastName = "Bhanderi" },
                new Customer { ID = 17, FirstName = "Ankit"    , LastName = "Ramani" },
                new Customer { ID = 18, FirstName = "Sanket"   , LastName = "Shah" } ,
                new Customer { ID = 19, FirstName = "Amit"     , LastName = "Shah" } ,
                new Customer { ID = 20, FirstName = "Nilesh"   , LastName = "Soni" }
            };
            var results = from c in customers
                          where c.FirstName.StartsWith("San")
                          select c;
            //使用Parallel并行查询
            var resultsUserParallel = from c in customers.AsParallel()
                          where c.FirstName.StartsWith("San")
                          select c;
            //对并行查询的结果排序，AsOrdered影响性能，最好不用
            var resultsUserAsOrdered = from c in customers.AsParallel().AsOrdered()
                          where c.FirstName.StartsWith("San")
                          select c;
            //强制使用Parallel并行查询，如果让AsParallel自己决定的话
            //有可能它会选择原来的Linq的执行方式
            var resultsForceParallelism = from c in customers.AsParallel().WithExecutionMode
            (ParallelExecutionMode.ForceParallelism)
                          where c.FirstName.StartsWith("San")
                          select c;
            //确定并行执行使用CPU的最多的数量
            var resultsDegreeOfParallelism = from c in customers.AsParallel().WithDegreeOfParallelism(2)
                          where c.FirstName.StartsWith("San")
                          select c;
            //随机产生一个有序的数
            IEnumerable<int> evens = ((ParallelQuery<int>)ParallelEnumerable.Range(0, 50000))
                .Where(i => i % 2 == 0)
                .Select(i => i).ToList();
            //使用并行产生重复的数字ParallelQuery<TResult>
            int sum = ParallelEnumerable.Repeat(2, 50000).Select(i => i).Sum();
            Console.WriteLine(sum);
            Console.ReadKey();
        }
    }

    public class Customer
    {
        public int ID { get; set; }
        public string FirstName { get; set; }
        public string LastName { get; set; }
    }
}