在PowerShell中异步调用System.Action实例

Question

背景

首先我创建一个System.Action实例：

PS C:\Users\KnutKristian> $a = [Action]{}

看一下成员：

PS C:\Users\KnutKristian> $a | gm

   TypeName: System.Action

Name              MemberType Definition                                        
----              ---------- ----------                                        
BeginInvoke       Method     System.IAsyncResult BeginInvoke(System.AsyncCal...
Clone             Method     System.Object Clone(), System.Object ICloneable...
DynamicInvoke     Method     System.Object DynamicInvoke(Params System.Objec...
EndInvoke         Method     void EndInvoke(System.IAsyncResult result)        
Equals            Method     bool Equals(System.Object obj)                    
GetHashCode       Method     int GetHashCode()                                 
GetInvocationList Method     System.Delegate[] GetInvocationList()             
GetObjectData     Method     void GetObjectData(System.Runtime.Serialization...
GetType           Method     type GetType()                                    
Invoke            Method     void Invoke()                                     
ToString          Method     string ToString()                                 
Method            Property   System.Reflection.MethodInfo Method {get;}        
Target            Property   System.Object Target {get;}

BeginInvoke签名：

PS C:\Users\KnutKristian> $a.BeginInvoke.OverloadDefinitions
System.IAsyncResult BeginInvoke(System.AsyncCallback callback, System.Object ob
ject)

当我尝试开始调用时，我收到此错误：

PS C:\Users\KnutKristian> $a.BeginInvoke($null, $null)
Exception calling "BeginInvoke" with "2" argument(s): "The object must be a run
time Reflection object."
At line:1 char:1
+ $a.BeginInvoke($null, $null)
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [], MethodInvocationException
    + FullyQualifiedErrorId : ArgumentException

指定内容无济于事：

PS C:\Users\…> $a.BeginInvoke([AsyncCallback]{param([IAsyncResult] $a)}, '')
Exception calling "BeginInvoke" with "2" argument(s): "The object must be a run
time Reflection object."
At line:1 char:1
+ $a.BeginInvoke([AsyncCallback]{param([IAsyncResult] $a)}, '')
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [], MethodInvocationException
    + FullyQualifiedErrorId : ArgumentException

一些例外信息：

PS C:\Users\KnutKristian> $Error[0].Exception.InnerException | gm


   TypeName: System.ArgumentException

Name             MemberType Definition                                         
----             ---------- ----------                                         
Equals           Method     bool Equals(System.Object obj), bool _Exception....
GetBaseException Method     System.Exception GetBaseException(), System.Exce...
GetHashCode      Method     int GetHashCode(), int _Exception.GetHashCode()    
GetObjectData    Method     void GetObjectData(System.Runtime.Serialization....
GetType          Method     type GetType(), type _Exception.GetType()          
ToString         Method     string ToString(), string _Exception.ToString()    
Data             Property   System.Collections.IDictionary Data {get;}         
HelpLink         Property   string HelpLink {get;set;}                         
HResult          Property   int HResult {get;}                                 
InnerException   Property   System.Exception InnerException {get;}             
Message          Property   string Message {get;}                              
ParamName        Property   string ParamName {get;}                            
Source           Property   string Source {get;set;}                           
StackTrace       Property   string StackTrace {get;}                           
TargetSite       Property   System.Reflection.MethodBase TargetSite {get;}


PS C:\Users\KnutKristian> $Error[0].Exception.InnerException |
    fl Message, ParamName, InnerException -Force


Message        : The object must be a runtime Reflection object.
ParamName      : 
InnerException : 

问题

1. 消息是什么

     

   对象必须是运行时Reflection对象。

   在这种背景下意味着什么？据我所知，这里只有.NET对象。也许抱怨一些PowerShell的具体细节？

2. 如何成功运行BeginInvoke方法？

Answer 1

请尝试以下代码。

[Action]{}|%{$_.BeginInvoke($null, $null)}


IsCompleted            : True
AsyncDelegate          : System.Action
AsyncState             :
CompletedSynchronously : False
EndInvokeCalled        : False
AsyncWaitHandle        : System.Threading.ManualResetEvent
NextSink               :

请查看以下文章以了解RunTimeType http://msdn.microsoft.com/en-us/library/ms172329.aspx

Answer 2

要以异步方式运行，您可以尝试jobs（多进程方式，效率不高），或者您可以尝试创建RunspacePool，如this post所示。