[C#] Async Lambda as delegate

目標：透過.NET Framework 4.5後的Async， 與Lambda建立非同步委派。

1.      原始非同步程式碼：

u  主程式

static void Main(string[] args) { var myNumbers = new List<int>(){                 10,20,30,40,50,60,70,80,90,100,110,120,15             }; //Async Test testAsync(myNumbers); Console.WriteLine("End"); Console.ReadKey(); } private static void testAsync (IEnumerable<int> myNumbers) { using (var asyncTest = new AsyncLambda()){     asyncTest.AsyncGetData(myNumbers); //Call async method directly } }

u  AsyncLambda

public class AsyncLambda : IDisposable { public async Task<IEnumerable<int>> AsyncGetData(IEnumerable<int> myNumbers) {             await Task.Delay(3000);             var filteredData = myNumbers.Where(x => x < 100);             foreach (var num in filteredData)                 Console.WriteLine(num.ToString());             return filteredData; } }

u  Output :

End 10 20 30 40 50 60 70 80 90 15

2.      Async Lambda as a delegate

u  將原有的非同步方法改成委派(Func) :

※注意在Lambda前面必須宣告一個 async (非同步)

public void GetCollection(IEnumerable<int> myNumbers) {     Func<IEnumerable<int>, Task<IEnumerable<int>>> myEvent = async (x) =>             {                 await Task.Delay(3000);                 var filteredData = x.Where(p => p < 100);                 foreach (var num in filteredData)                     Console.WriteLine(num.ToString());                 return filteredData;             };    myEvent.Invoke(myNumbers); }

u  主程式改一下叫用的方法

private static void testAsyncLambda(IEnumerable<int> myNumbers) { using (var asyncTest = new AsyncLambda()) { asyncTest.GetCollection(myNumbers); //Using async delegate      //asyncTest.AsyncGetData(myNumbers); //Call async method directly } }

u  Output :

End 10 20 30 40 50 60 70 80 90 15