前言

在.net4.0以后异步操作,并行计算变得异常简单,但是由于公司项目开发基于.net3.5所以无法用到4.0的并行计算以及Task等异步编程。因此,为了以后更方便的进行异步方式的开发,我封装实现了异步编程框架,通过BeginInvoke、EndInvoke的方式实现异步编程。

框架结构

整个框架包括四个部分

1. 基类抽象Opeartor
   异步操作的基类，实现了异步操作接口
2. FuncAsync
   异步的Func
3. ActionAsync
   异步的Action

4. Asynchorus
   对ActionAsync和FuncAsync的封装

   Operator

   Operator是一个抽象类,实现了IOperationAsync和IContinueWithAsync两个接口。
   IOperationAsync实现了异步操作,IContinueWithAsync实现了类似于Task的ContinueWith方法,在当前异步操作完成后继续进行的操作

   IOperationAsync接口详解

    public interface IOperationAsync{IAsyncResult Invoke();void Wait();void CompletedCallBack(IAsyncResult ar);void CatchException(Exception exception);}

• Invoke():异步方法的调用
• Wait():等待异步操作执行
• CompletedCallBack():操作完成回调
• CatchException():抓取异常

IContinueWithAsync接口详情

public interface IContinueWithAsync
{Operator Previous { get; set; }Operator Next { get; set; }Operator ContinueWithAsync(Action action);Operator ContinueWithAsync<TParameter>(Action<TParameter> action, TParameter parameter);
}

• Previous:前一个操作
• Next:下一个操作
• ContinueWithAsync():异步继续操作

public abstract class Operator : IOperationAsync, IContinueWithAsync
{public IAsyncResult Middle;public readonly string Id;public Exception Exception { get; private set; }public Operator Previous { get; set; }public Operator Next { get; set; }protected Operator(){Id = Guid.NewGuid().ToString();}public abstract IAsyncResult Invoke();protected void SetAsyncResult(IAsyncResult result){this.Middle = result;}public virtual void Wait(){if (!Middle.IsCompleted) Middle.AsyncWaitHandle.WaitOne();}public virtual void CompletedCallBack(IAsyncResult ar){}public void CatchException(Exception exception){this.Exception = exception;}protected Operator ContinueAsync(){if (Next != null) Next.Invoke();return Next;}public virtual Operator ContinueWithAsync(Action action){Next = new ActionAsync(action);Next.Previous = this;return Next;}public virtual Operator ContinueWithAsync<TParameter>(Action<TParameter> action, TParameter parameter){Next = new ActionAsync<TParameter>(action, parameter);Next.Previous = this;return Next;}public virtual Operator ContinueWithAsync<TResult>(Func<TResult> func){Next = new FuncAsync<TResult>();Next.Previous = this;return Next;}public virtual Operator ContinueWithAsync<TParameter, TResult>(Func<TParameter, TResult> func,TParameter parameter){Next = new FuncAsync<TParameter, TResult>(func, parameter);Next.Previous = this;return Next;}
}

无返回异步操作

ActionAsync

public class ActionAsync : Operator
{private readonly Action _action;protected ActionAsync(){}public ActionAsync(Action action): this(){this._action = action;}public override IAsyncResult Invoke(){var middle = _action.BeginInvoke(CompletedCallBack, null);SetAsyncResult(middle);return middle;}public override void CompletedCallBack(IAsyncResult ar){try{_action.EndInvoke(ar);}catch (Exception exception){this.CatchException(exception);}ContinueAsync();}
}
public class ActionAsync<T> : ActionAsync
{public T Result;private readonly Action<T> _action1;protected readonly T Parameter1;public ActionAsync(){}public ActionAsync(T parameter){this.Parameter1 = parameter;}public ActionAsync(Action<T> action, T parameter){this._action1 = action;this.Parameter1 = parameter;}public override IAsyncResult Invoke(){var result = _action1.BeginInvoke(Parameter1, CompletedCallBack, null);SetAsyncResult(result);return result;}public override void CompletedCallBack(IAsyncResult ar){try{_action1.EndInvoke(ar);}catch (Exception exception){this.CatchException(exception);}ContinueAsync();}
}

有返回异步

FuncAsync实现了IFuncOperationAsync接口

IFuncOperationAsync

public interface IFuncOperationAsync<T>
{void SetResult(T result);T GetResult();
}

• SetResult(T result):异步操作完成设置返回值

• GetResult():获取返回值

  FuncAsync

public class FuncAsync<TResult> : Operator, IFuncOperationAsync<TResult>
{private TResult _result;public TResult Result{get{if (!Middle.IsCompleted || _result == null){_result = GetResult();}return _result;}}private readonly Func<TResult> _func1;public FuncAsync(){}public FuncAsync(Func<TResult> func){this._func1 = func;}public override IAsyncResult Invoke(){var result = _func1.BeginInvoke(CompletedCallBack, null);SetAsyncResult(result);return result;}public override void CompletedCallBack(IAsyncResult ar){try{var result = _func1.EndInvoke(ar);SetResult(result);}catch (Exception exception){this.CatchException(exception);SetResult(default(TResult));}ContinueAsync();}public virtual TResult GetResult(){Wait();return this._result;}public void SetResult(TResult result){_result = result;}
}
public class FuncAsync<T1, TResult> : FuncAsync<TResult>
{protected readonly T1 Parameter1;private readonly Func<T1, TResult> _func2;public FuncAsync(Func<T1, TResult> action, T1 parameter1): this(parameter1){this._func2 = action;}protected FuncAsync(T1 parameter1): base(){this.Parameter1 = parameter1;}public override IAsyncResult Invoke(){var result = _func2.BeginInvoke(Parameter1, CompletedCallBack, null);SetAsyncResult(result);return result;}public override void CompletedCallBack(IAsyncResult ar){try{var result = _func2.EndInvoke(ar);SetResult(result);}catch (Exception exception){CatchException(exception);SetResult(default(TResult));}ContinueAsync();}
}

Asynchronous 异步操作封装

ActionAsync和FuncAsync为异步操作打下了基础,接下来最重要的工作就是通过这两个类执行我们的异步操作,为此我封装了一个异步操作类
主要封装了以下几个部分：

1. WaitAll(IEnumerable<Operator> operations):等待所有操作执行完毕
2. WaitAny(IEnumerable<Operator> operations):等待任意操作执行完毕
3. ActionAsync
4. FuncAsync
5. ContinueWithAction

6. ContinueWithFunc

   后面四个包含若干个重载,这里只是笼统的代表一个类型的方法

   WaitAll

public static void WaitAll(IEnumerable<Operator> operations)
{foreach (var @operator in operations){@operator.Wait();}
}

WaitAny

public static void WaitAny(IEnumerable<Operator> operations)
{while (operations.All(o => !o.Middle.IsCompleted))Thread.Sleep(100);
}

等待时间可以自定义

ActionInvoke

public static Operator Invoke(Action action)
{Operator operation = new ActionAsync(action);operation.Invoke();return operation;
}
public static Operator Invoke<T>(Action<T> action, T parameter)
{Operator operation = new ActionAsync<T>(action, parameter);operation.Invoke();return operation;
}
public static Operator Invoke<T1, T2>(Action<T1, T2> action, T1 parameter1, T2 parameter2)
{Operator operation = new ActionAsync<T1, T2>(action, parameter1, parameter2);operation.Invoke();return operation;
}

FuncInvoke

public static Operator Invoke<TResult>(Func<TResult> func)
{Operator operation = new FuncAsync<TResult>(func);operation.Invoke();return operation;
}
public static Operator Invoke<TParameter, TResult>(Func<TParameter, TResult> func, TParameter parameter)
{TParameter param = parameter;Operator operation = new FuncAsync<TParameter, TResult>(func, param);operation.Invoke();return operation;
}
public static Operator Invoke<T1, T2, TResult>(Func<T1, T2, TResult> func, T1 parameter1, T2 parameter2)
{Operator operation = new FuncAsync<T1, T2, TResult>(func, parameter1, parameter2);operation.Invoke();return operation;
}

ContinueWithAction

public static Operator ContinueWithAsync(IEnumerable<Operator>operators, Action action)
{return Invoke(WaitAll, operators).ContinueWithAsync(action);
}
public static Operator ContinueWithAsync<TParameter>(IEnumerable<Operator> operators, Action<TParameter> action, TParameter parameter)
{return Invoke(WaitAll, operators).ContinueWithAsync(action, parameter);
}

ContinueWithFunc

public static Operator ContinueWithAsync<TResult>(IEnumerable<Operator> operators,Func<TResult> func)
{return Invoke(WaitAll, operators).ContinueWithAsync(func);
}
public static Operator ContinueWithAsync<TParameter, TResult>(IEnumerable<Operator> operators, Func<TParameter, TResult> func, TParameter parameter)
{return Invoke(WaitAll, operators).ContinueWithAsync(func, parameter);
}

这里有个bug当调用ContinueWithAsync后无法调用Wait等待,本来Wait需要从前往后等待每个异步操作,但是测试了下不符合预期结果。不过理论上来说应该无需这样操作,ContinueWithAsync只是为了当上一个异步操作执行完毕时继续执行的异步操作,若要等待,那不如两个操作放到一起,最后再等待依然可以实现。

前面的都是单步异步操作的调用,若需要对某集合进行某个方法的异步操作,可以foreach遍历

public void ForeachAsync(IEnumerbale<string> parameters)
{foreach(string p in parameters){Asynchronous.Invoke(Tast,p);}
}
public void Test(string parameter)
{//TODO:做一些事
}

每次都需要去手写foreach,比较麻烦,因此实现类似于PLinq的并行计算方法实在有必要,不过有一点差别,PLinq是采用多核CPU进行并行计算,而我封装的仅仅遍历集合进行异步操作而已

ForeachAction

public static IEnumerable<Operator> Foreach<TParameter>(IEnumerable<TParameter> items, Action<TParameter> action)
{return items.Select(t => Invoke(action, t)).ToList();
}

ForeachFunc

public static IEnumerable<Operator> Foreach<TParameter, TResult>(IEnumerable<TParameter> items, Func<TParameter, TResult> func)
{return items.Select(parameter => Invoke(func, parameter)).ToList();
}

如何使用

• 无返回值异步方法调用

public void DoSomeThing()
{//TODO:
}

通过Asynchronous.Invoke(DoSomeThing) 执行

public void DoSomeThing(string parameter)
{//TODO:
}

通过Asynchronous.Invoke(DoSomeThing,parameter) 执行

• 有返回值异步方法调用

public string DoSomeThing()
{//TODO:
}

通过Asynchronous.Invoke(()=>DoSomeThing())执行

public string DoSomeThing(string parameter)
{//TODO:
}

通过Asynchronous.Invoke(()=>DoSomeThing(parameter))执行,或者也可以传入参数通过Asynchronous.Invoke(p=>DoSomeThing(p),parameter)

• 无返回值Foreach

public void Test
{int[] parameters = {1,2,3,4,5};Asynchronous.Foreach(parameters,Console.WriteLine);
}

• 有返回值Foreach

public void Test
{int[] parameters = {1,2,3,4,5};var operators = Asynchronous.Foreach(parameters,p=> p*2);Asynchrous.WaitAll(operators);Asynchronous.Foreach(operators.Cast<FuncAsync<int,int>>(),p=> Console.WriteLine(p.Result));
}

首先将集合每个值扩大2倍,然后输出

• 异步执行完再执行

public void Test
{int[] parameters = {1,2,3,4,5};var operators = Asynchronous.Foreach(parameters,p=> p*2);Asynchrous.ContinueWithAsync(operators,Console.WriteLine,"执行完成");
}

• 每次执行完继续执行
  可能有时候我们需要遍历一个集合,每个元素处理完成后我们需要输出XX处理完成

public void Test
{int[] parameters = {1,2,3,4,5};var operators = Asynchronous.Foreach(parameters,p=> p*2);Asynchronous.Foreach(operators,o=>{o.ContinueWithAsync(()={//每个元素执行完时执行if(o.Exception != null){//之前执行时产生未处理的异常,这里可以捕获到  }});});
}

• 可以实现链式异步操作

public void Chain()
{Asynchronous.Invoke(Console.WriteLine,1).ContinueWithAsync(Console.WriteLine,2).ContinueWithAsync(Console.WriteLine,3)
}

这样会按步骤输出1,2,3

结束语

以上只是列出了部分重载方法,其他重载方法无非就是加参数,本质实际是一样的,具体可以已提交至github。我还封装了for方法,但是感觉没什么用,而且也从没有用到过,这里不再提
通过以上的封装,已经能完成日常大部分的操作,调用还是比较方便的。

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