How to create a WaitHandle on a native HANDLE?

[nickdu]

I'm using interop (PInvoke) to call a method
(FindFirstPrinterChangeNotification) which returns an event handle. I would
like to stay as much as possible in managed code so I want to get this native
event handle into a managed WaitHandle so I can call one of the WaitHandle's
Wait() methods. How do I do this?

The only way I see is to either:

1. Create an EventWaitHandle instance and then set the SafeWaitHandle
property. The problem with this route is that it will first create an event
object that I don't need.

2. Derive a class from WaitHandle so that I can get access to its protected
constructor which accepts a SafeWaitHandle.

Is there some other way? I was hoping there was an exposed way to create a
WaitHandle from a native event handle.
--
Thanks,
Nick

(e-mail address removed)
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[Mark Salsbery [MVP]]

I'm using interop (PInvoke) to call a method
(FindFirstPrinterChangeNotification) which returns an event handle. I
would
like to stay as much as possible in managed code so I want to get this
native
event handle into a managed WaitHandle so I can call one of the
WaitHandle's
Wait() methods. How do I do this?

The only way I see is to either:

1. Create an EventWaitHandle instance and then set the SafeWaitHandle
property. The problem with this route is that it will first create an
event
object that I don't need.

2. Derive a class from WaitHandle so that I can get access to its
protected
constructor which accepts a SafeWaitHandle.

I'd personally go with option 2, not necessarily just to get access to a
protected constructor, but because the WaitHandle class is designed to wrap
a native OS handle.

Seems like a simple, clean solution to me.

Mark

 

[Hongye Sun [MSFT]]

Hi Nick,

Thanks for your posting.

Personally, I agree with Mark that option #2 is the cleanest resolution for
this issue. I don't know any other better ways to do this job.

For your reference, here is an examle and it is similar to option #1:
http://www.codeproject.com/KB/printing/qPrintcomponent2.aspx

The difference is that it is using ManualResetEvent and
ThreadPool.RegisterWaitForSingleObject.

Hope it helps.

Regards,
Hongye Sun ([email protected], remove 'online.')
Microsoft Online Community Support

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