c#语法糖汇总

todo

C#9.0

https://docs.microsoft.com/zh-cn/dotnet/csharp/whats-new/csharp-9

C#8.0

https://docs.microsoft.com/zh-cn/dotnet/csharp/whats-new/csharp-8

yield return的作用

在 return 时，保存当前函数的状态，下次调用时继续从当前位置处理。

        static void Main(string[] args)
        {
            foreach (var item in GetNumbers())
            {
                Console.WriteLine("Main process. item = " + item);
                break;
            }
            Console.ReadKey();
                
        }
        static IEnumerable<int> GetNumbers()
        {
            // 以[0, 1, 2] 初始化数列 list
            Console.WriteLine("Initializating...");
            List<int> list = new List<int>();
            for (int i = 0; i < 3; i++)
                list.Add(i);

            // 每次 yield return 返回一个list的数据
            Console.WriteLine("Processing...");
            for (int i = 0; i < list.Count; i++)
            {
                Console.WriteLine("Yield called.");
                yield return list[i];
            }
            Console.WriteLine("Done.");
        }

输出

Initializating...
Processing...
Yield called.
Main process. item = 0

代码

        static void Main(string[] args)
        {
            foreach (var item in GetNumbers())
            {
                Console.WriteLine("Main process. item = " + item);
            }
            Console.ReadKey();
                
        }
        static IEnumerable<int> GetNumbers()
        {
            // 以[0, 1, 2] 初始化数列 list
            Console.WriteLine("Initializating...");
            List<int> list = new List<int>();
            for (int i = 0; i < 3; i++)
                list.Add(i);

            // 每次 yield return 返回一个list的数据
            Console.WriteLine("Processing...");
            for (int i = 0; i < list.Count; i++)
            {
                Console.WriteLine("Yield called.");
                yield return list[i];
            }
            Console.WriteLine("Done.");
        }

输出

Initializating...
Processing...
Yield called.
Main process. item = 0
Yield called.
Main process. item = 1
Yield called.
Main process. item = 2
Done.