Re: Invoking a form that was created on a separate thread

Hi Daniel

The my problem occurs in that the new form and all its controls only get
created by the parsing routine, its a bit like xaml so all the form
definition is in the xml file that is parsed, So I need to be able to parse
these files which can take a while on the XDA's but still give progress back
and be able to interact with the code behind (the class that instantiated
the parsing) once the form is created and showed.

Sorry if I'm not quite getting this.
Thanks
Dan

"Daniel Moth" <dmoth74@xxxxxxxxxxx> wrote in message
news:%23ifZhDmQFHA.2788@xxxxxxxxxxxxxxxxxxxxxxx
> Don't return a form from a background thread. The form should be on the
> main form. It is the progress info (percentage and possibly status text)
> that you return to the main thread/form from the background thread. With
> backgroundWorker you don't need to explicitly invoke anything. Keep your
> parsing on the background thread if you have calculated that it takes too
> long and hence would block the UI.
>
> Whether you are using the BW from my site (VB version) or from opennetcf
> (C# version), the sample here should help:
> http://www.danielmoth.com/Blog/2004/12/backgroundworker-sample.html
>
> Cheers
> Daniel
> --
> http://www.danielmoth.com/Blog/
>
>
> "Dannyboy" <daniel@xxxxxxxxxxxxxxxxxxxxxxx> wrote in message
> news:uH18yffQFHA.3988@xxxxxxxxxxxxxxxxxxxxxxx
>> Hi Daniel thanks for that I shall go through your background worker code,
>> I do currently have a background process implemenation that is based on
>> an article written by Rocky Lhotka on msdn
>> http://msdn.microsoft.com/vbasic/using/columns/adventures/default.aspx?pull=/library/en-us/dnadvnet/html/vbnet09272002.asp
>> the trouble is the blasted form that is returned from that background
>> process throws an exception everytime I try and invoke its show method.
>>
>> Should I be changing the implementation so that I don't do the parsing on
>> the background thread?
>>
>> Dan
>>
>> "Daniel Moth" <dmoth74@xxxxxxxxxxx> wrote in message
>> news:enGb7SfQFHA.508@xxxxxxxxxxxxxxxxxxxxxxx
>>> Check out the BackgroundWorker or do it yourself (parsing on thread and
>>> updating the form with control invoke)
>>>
>>> Cheers
>>> Daniel
>>> --
>>> http://www.danielmoth.com/Blog/
>>>
>>>
>>> "Dannyboy" <daniel@xxxxxxxxxxxxxxxxxxxxxxx> wrote in message
>>> news:%23bFkZNfQFHA.248@xxxxxxxxxxxxxxxxxxxxxxx
>>>> Hi Chris your right its not good all, the the thing is the xml files
>>>> that are being parsed are pretty big and they take quite a bit of time,
>>>> so I need to put a progress bar on, I did try creating that on the main
>>>> the and then updating that from a separate thread.
>>>>
>>>> If there is a better way to do this I'm open to all suggestions cos
>>>> this is p#@*ing me off
>>>>
>>>> Thanks
>>>> Dan
>>>> "Chris Tacke, eMVP" <ctacke@xxxxxxxxxxxxxxxxxxxxxx> wrote in message
>>>> news:u9%23zJ0dQFHA.1528@xxxxxxxxxxxxxxxxxxxxxxx
>>>>> The first question has to be why are you creating a Form on another
>>>>> thread? It's a very bad idea, a bad design, and bad practice.
>>>>>
>>>>>
>>>>> --
>>>>> Chris Tacke
>>>>> Co-founder
>>>>> OpenNETCF.org
>>>>> Has OpenNETCF helped you? Consider donating to support us!
>>>>> http://www.opennetcf.org/donate
>>>>>
>>>>>
>>>>> "Dan" <daniel@xxxxxxxxxxxxxxxxxxxxxxx> wrote in message
>>>>> news:e5x$vrdQFHA.3628@xxxxxxxxxxxxxxxxxxxxxxx
>>>>>> Hi everyone
>>>>>>
>>>>>> I have a class which parses an xml file and creates a form and its
>>>>>> controls from it, and I have recenlty moved this so that it happens
>>>>>> on its own thread, I know about controls that are created on a
>>>>>> different thread to the UI can not just have its methods called
>>>>>> without using invoke so with this I have tried several different ways
>>>>>> to get the form to show but I'm having problems.
>>>>>>
>>>>>> The ways I have have tried are:
>>>>>>
>>>>>> 1. With the form that is returned from the parsing class I have tried
>>>>>> me.invoke(new delegateSub(addressof newform.show))
>>>>>> This throws the error "Cannot call Invoke or InvokeAsync on a
>>>>>> control until the window handle has been created."
>>>>>>
>>>>>> 2. Add a controller class that is also created on the separate thread
>>>>>> which shows the form when the parsing is complete, this does show the
>>>>>> form briefly but it then disappears.
>>>>>>
>>>>>> 3. With the same controller class I use Application.Run(parsedform).
>>>>>> This works beautifully apart from one small snag, the class which
>>>>>> starts the parsing is passed a reference to the parser and acts as
>>>>>> the code behind for the the controls that are created in the parsed
>>>>>> form e.g. the click event of a button in the parsed form is handled
>>>>>> by a method in the class that is sent to the parser. This is where
>>>>>> this method seems to fall down because the reference no longer works.
>>>>>>
>>>>>> Am I fighting a loosing battle with this or can anyone offer some
>>>>>> code of wisdom.
>>>>>> Any help will be much appreciated.
>>>>>>
>>>>>> Many Thanks
>>>>>> Dan
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>
>>
>>
>


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