[Ironpython-users] ShowDialog Hangs

[Andrew Graham]

Not really strange, expected behaviour in fact. The Form is drawn OK but 
there is no message loop running on the thread to pump messages to it so it 
will be unresponsive and sit there until the thread exits.  A modal dialog, 
or Form shown modally, tries to pump the message queue itself, that is how 
it acheives modality, and as my previous email to you stated, as there is no 
message loop on your thread for it to pump so that is probably why it hangs.

Regards

Andy graham

-----Original Message----- 
From: Andrew Ayre
Sent: Wednesday, February 25, 2015 4:41 PM
To: ironpython-users at python.org
Subject: Re: [Ironpython-users] ShowDialog Hangs

Thanks for the responses. Strangely the following script works:

import clr
import time
clr.AddReference("System.Windows.Forms")
from System.Windows.Forms import OpenFileDialog, DialogResult, Form
F = Form()
F.Show()
time.sleep(5)

This displays a form and then closes it when the script ends after five
seconds.

However simply swapping F.Show for OpenFileDialog().ShowDialog() causes
the script to hang.

I will check the suggestions made, but I wondered if this behavior with
the form gives anyone some additional clues.

Thanks, Andy

On 2/25/2015 2:50 PM, Slide wrote:
> You need to make sure the thread was started as an STAThread I believe,
> otherwise the common windows controls (OpenFileDialog being one of them)
> won't work correctly.
>
> On Wed Feb 25 2015 at 2:02:32 AM Andrew Ayre <andy at britishideas.com
> <mailto:andy at britishideas.com>> wrote:
>
>     I am sure I am making a silly mistake somewhere.
>
>     I have IronPython embedded in my C# WinForms application.
>
>     The interpreter is running in a thread that has been created for it.
>     I.e. not the UI thread.
>
>     Everything works fine until the call to Dialog.ShowDialog, at which
>     point execution of IronPython hangs and no dialog appears.
>
>     I'm guessing that this is because the interpreter is not running in 
> the
>     UI thread (which I don't want to do because sometimes scripts can take 
> a
>     long time to execute, depending on what they are doing).
>
>     This is my first attempt using WinForms from scripting in my
>     application.
>
>     Any hints or suggestions on how I can debug this, synchronize with the
>     UI thread or something else?
>
>     Thanks! Andy
>
>     import clr
>     clr.AddReference("System.__Windows.Forms")
>     from System.Windows.Forms import OpenFileDialog, DialogResult
>
>     Dialog = OpenFileDialog()
>     Dialog.ShowDialog()
>
>     --
>     Andy
>     PGP Key ID: 0xDC1B5864
>     _________________________________________________
>     Ironpython-users mailing list
>     Ironpython-users at python.org <mailto:Ironpython-users at python.org>
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>

-- 
Andy
PGP Key ID: 0xDC1B5864
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