> Gregory Gadow wrote:
> > I've cobbled together a PrinterClass that takes a text file and dumps it
> > to a printer. The app using is has multiple threads, all of which need
> > access to a shared instance. Can someone point me to an example of
> > multiple threads synchronized to use a single shared resource?
> > --
> > Gregory Gadow
> >
> >
>
> You are not sending it to a windows printer queue? Usually windows takes
> care of this for you.
>
> If you are doing something funny you should think about using one thread
> to do the job and having a queue that holds the jobs.  All the worker
> threads just can add to the queue, the printer thread then processes the
> queue.

> Chris wrote:
>
>
>>Gregory Gadow wrote:
>>
>>>I've cobbled together a PrinterClass that takes a text file and dumps it
>>>to a printer. The app using is has multiple threads, all of which need
>>>access to a shared instance. Can someone point me to an example of
>>>multiple threads synchronized to use a single shared resource?
>>>--
>>>Gregory Gadow
>>>
>>>
>>
>>You are not sending it to a windows printer queue? Usually windows takes
>>care of this for you.
>>
>>If you are doing something funny you should think about using one thread
>>to do the job and having a queue that holds the jobs.  All the worker
>>threads just can add to the queue, the printer thread then processes the
>>queue.
>
>
> The whole class is a bit much to cut-n-paste, but basically, it is built
> around this declaration:
>
> Private Shared WithEvents pd as PrintDocument
>
> The public function that invokes the class is
>
> Public Function SendFileToPrinter(ByVal ThisFile As String, ByVal ThisPrinter
> As String) _
> As Boolean
>
> which creates a new instance of pd (if necessary) and sets up margins,
> Landscape orientation, and tells pd what printer to use. Then, it opens the
> text file using a shared instance of StreamReader and calls pd.Print(). The
> .NET library takes over and, at the start of each new page of text, calls
> pd_PrintPage by raising the PrintPage event on pd.
>
> pd_PrintPage is a private shared sub handling the PrintPage event of the pd
> object. It looks to the instance of StreamReader to fetch the next line of the
> text document, then calls Graphics.DrawString to draw the text to the printer.
> The routine then reads the next line, looping until either a maximum number of
> lines has been read, a form feed character is encountered or the end of file
> is reached. When all of the pages have been printed (indicated by setting
> HasMorePages = False in the event parameter, ev As PrintPageEventArgs), the
> call to pd.Print() returns. SendFileToPrinter then ties up any loose ends and
> returns with true if there were no errors or false if there were.
>
> Yes, all I need is to dump a text file to a network printer, but that seems to
> be impossible under .NET 2.0 :-/
>
> Anyway, this class worked great until I went to a threaded version of a
> service I've written. I need to figure out how to make PrinterClass
> thread-safe and allow only one thread to use it at a time. I don't think
> allowing multiple instances of the class would work, as you will still have
> competing processes trying to control the one physical printer. As now
> written, all of the class internals are shared, both the declares and the two
> methods.
> --
> Gregory Gadow
>

> Gregory Gadow wrote:
> > Chris wrote:
> >
> >
> >>Gregory Gadow wrote:
> >>
> >>>I've cobbled together a PrinterClass that takes a text file and dumps it
> >>>to a printer. The app using is has multiple threads, all of which need
> >>>access to a shared instance. Can someone point me to an example of
> >>>multiple threads synchronized to use a single shared resource?
> >>>--
> >>>Gregory Gadow
> >>>
> >>>
> >>
> >>You are not sending it to a windows printer queue? Usually windows takes
> >>care of this for you.
> >>
> >>If you are doing something funny you should think about using one thread
> >>to do the job and having a queue that holds the jobs.  All the worker
> >>threads just can add to the queue, the printer thread then processes the
> >>queue.
> >
> >
> > The whole class is a bit much to cut-n-paste, but basically, it is built
> > around this declaration:
> >
> > Private Shared WithEvents pd as PrintDocument
> >
> > The public function that invokes the class is
> >
> > Public Function SendFileToPrinter(ByVal ThisFile As String, ByVal ThisPrinter
> > As String) _
> > As Boolean
> >
> > which creates a new instance of pd (if necessary) and sets up margins,
> > Landscape orientation, and tells pd what printer to use. Then, it opens the
> > text file using a shared instance of StreamReader and calls pd.Print(). The
> > .NET library takes over and, at the start of each new page of text, calls
> > pd_PrintPage by raising the PrintPage event on pd.
> >
> > pd_PrintPage is a private shared sub handling the PrintPage event of the pd
> > object. It looks to the instance of StreamReader to fetch the next line of the
> > text document, then calls Graphics.DrawString to draw the text to the printer.
> > The routine then reads the next line, looping until either a maximum number of
> > lines has been read, a form feed character is encountered or the end of file
> > is reached. When all of the pages have been printed (indicated by setting
> > HasMorePages = False in the event parameter, ev As PrintPageEventArgs), the
> > call to pd.Print() returns. SendFileToPrinter then ties up any loose ends and
> > returns with true if there were no errors or false if there were.
> >
> > Yes, all I need is to dump a text file to a network printer, but that seems to
> > be impossible under .NET 2.0 :-/
> >
> > Anyway, this class worked great until I went to a threaded version of a
> > service I've written. I need to figure out how to make PrinterClass
> > thread-safe and allow only one thread to use it at a time. I don't think
> > allowing multiple instances of the class would work, as you will still have
> > competing processes trying to control the one physical printer. As now
> > written, all of the class internals are shared, both the declares and the two
> > methods.
> > --
> > Gregory Gadow
> >
>
> I still think if load your print documents into a queue and let a thread
>   that just processes the queue pull stuff out of the queue, you'd solve
> your problem.
>
> Then again, since you are just sending it to the windows print queue,
> I'd think it'd work anyways.