public class MyClass 
{ 
  public MyClass() 
  { 
    DisplayValue(); //這里不會(huì)阻塞 
    System.Diagnostics.Debug.WriteLine("MyClass() End."); 
  } 
  public Task<double> GetValueAsync(double num1, double num2) 
  { 
    return Task.Run(() => 
    { 
      for (int i = 0; i < 1000000; i++) 
      { 
        num1 = num1 / num2; 
      } 
      return num1; 
    }); 
  } 
  public async void DisplayValue() 
  { 
    double result = await GetValueAsync(1234.5, 1.01);//此處會(huì)開新線程處理GetValueAsync任務(wù)，然后方法馬上返回 
    //這之后的所有代碼都會(huì)被封裝成委托，在GetValueAsync任務(wù)完成時(shí)調(diào)用 
    System.Diagnostics.Debug.WriteLine("Value is : " + result); 
  } 
} 

public void DisplayValue() 
{ 
  System.Runtime.CompilerServices.TaskAwaiter<double> awaiter = GetValueAsync(1234.5, 1.01).GetAwaiter(); 
  awaiter.OnCompleted(() => 
    { 
      double result = awaiter.GetResult(); 
      System.Diagnostics.Debug.WriteLine("Value is : " + result); 
    }); 
}

public static class TaskAsyncHelper 
{ 
  /// <summary> 
  /// 將一個(gè)方法function異步運(yùn)行，在執(zhí)行完畢時(shí)執(zhí)行回調(diào)callback 
  /// </summary> 
  /// <param name="function">異步方法，該方法沒有參數(shù)，返回類型必須是void</param> 
  /// <param name="callback">異步方法執(zhí)行完畢時(shí)執(zhí)行的回調(diào)方法，該方法沒有參數(shù)，返回類型必須是void</param> 
  public static async void RunAsync(Action function, Action callback) 
  { 
    Func<System.Threading.Tasks.Task> taskFunc = () => 
    { 
      return System.Threading.Tasks.Task.Run(() => 
      { 
        function(); 
      }); 
    }; 
    await taskFunc(); 
    if (callback != null) 
      callback(); 
  } 
 
  /// <summary> 
  /// 將一個(gè)方法function異步運(yùn)行，在執(zhí)行完畢時(shí)執(zhí)行回調(diào)callback 
  /// </summary> 
  /// <typeparam name="TResult">異步方法的返回類型</typeparam> 
  /// <param name="function">異步方法，該方法沒有參數(shù)，返回類型必須是TResult</param> 
  /// <param name="callback">異步方法執(zhí)行完畢時(shí)執(zhí)行的回調(diào)方法，該方法參數(shù)為TResult，返回類型必須是void</param> 
  public static async void RunAsync<TResult>(Func<TResult> function, Action<TResult> callback) 
  { 
    Func<System.Threading.Tasks.Task<TResult>> taskFunc = ()=> 
      { 
        return System.Threading.Tasks.Task.Run(()=> 
          { 
            return function(); 
          }); 
      }; 
    TResult rlt = await taskFunc(); 
    if(callback != null) 
      callback(rlt); 
  } 
}