简单实现C#异步操作

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。

一、框架结构

整个框架包括四个部分

1、基类抽象Opeartor
我把每个异步执行过程称为一个Operate,因此需要一个Opeartor去执行
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

1）、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：

• WaitAll(IEnumerable<Operator> operations):等待所有操作执行完毕

• WaitAny(IEnumerable<Operator> operations):等待任意操作执行完毕

• ActionAsync

• FuncAsync

• ContinueWithAction

• 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。

希望对大家的学习有所帮助，在这祝大家新年快乐，新的一年大家一起努力。