[Gambas-user] Clearing data from TextAreas & ListBoxes
John Rose
john.aaron.rose at ...626...
Tue Mar 3 11:23:34 CET 2015
On 03/03/15 09:53, Tobias Boege wrote:
> On Tue, 03 Mar 2015, John Rose wrote:
>> On 03/03/15 08:31, Fabien Bodard wrote:
>>
>>> And th?? controls Will not be cleared until the procedure is not ended.
>>>
>>> Use an ascyncronous call to your external program can help you.
>>>
>>> You can use a timer trigger too that delay the call to the next event loop
>>> Le 2 mars 2015 21:35, "Tobias Boege" <taboege at ...626...> a ??crit :
>>>
>>>> On Mon, 02 Mar 2015, John Rose wrote:
>>>>> On 02/03/15 19:25, Tobias Boege wrote:
>>>>>> On Mon, 02 Mar 2015, John Rose wrote:
>>>>>>> I have a Click event on a Button. At runtime, clicking the button
>>>> should
>>>>>>> cause clearing of the data from a TextArea & some ListBoxes. There's
>>>> no
>>>>>>> way this 'clearance' cannot be executed as the Exec of a CL program
>>>>>>> (which definitely happens because it populates these controls) soon
>>>>>>> follows it. However, it doesn't seem to do so. Clearance coding:
>>>>>>> With StopListBox
>>>>>>> .Clear
>>>>>>> .Refresh
>>>>>>> End With
>>>>>>> With SteckersListBox
>>>>>>> .Clear
>>>>>>> .Refresh
>>>>>>> End With
>>>>>>> With ReflectorListBox
>>>>>>> .Clear
>>>>>>> .Refresh
>>>>>>> End With
>>>>>>> With RotorsListBox
>>>>>>> .Clear
>>>>>>> .Refresh
>>>>>>> End With
>>>>>>> With DetailTextArea
>>>>>>> .Clear
>>>>>>> .Refresh
>>>>>>> End With
>>>>>>>
>>>>>>> Is the above the correct method of causing the clearance to happen on
>>>>>>> the screen immediately?
>>>>>>>
>>>>>> That last word is important. Controls are refreshed during the event
>>>> loop
>>>>>> which you can think of as the pause mode of the interpreter: it enters
>>>> it
>>>>>> when there is no Gambas code to execute at present. The interpreter
>>>> sits
>>>>>> there waiting for events to happen or does maintenance like redrawing
>>>> the
>>>>>> GUI.
>>>>>>
>>>>>> You can force the interpreter to look at pending events (and to redraw
>>>> the
>>>>>> controls by the way!) by using the Wait instruction without argument.
>>>>>> Calling Refresh() is not necessary here which saves you 3 lines per
>>>> Clear()
>>>>>> call.
>>>>>>
>>>>> Tobi,
>>>>>
>>>>> I changed coding to:
>>>>> Public Sub RunButton_Click()
>>>>> ...
>>>>> StopListBox.Clear
>>>>> SteckersListBox.Clear
>>>>> ReflectorListBox.Clear
>>>>> RotorsListBox.Clear
>>>>> DetailTextArea.Clear
>>>>> Wait
>>>> Here, the controls are cleared.
>>>>
>>>>> ...
>>>>> aExecParameters = ["/opt/Enigma/turing_bombe_all_wheels", sMenuPath]
>>>>> 'sMenuPath points to an input file
>>>>> pturing_bombe = Exec aExecParameters Wait For Read As
>>>> "TuringBombeResultsDetail"
>>>>> ...
>>>>> PopulateListBoxesFromDetailsTextArea
>>>>> ...
>>>> Here, they are filled again with data from the external process.
>>>>
>>>>> End
>>>>>
>>>>> Public Sub TuringBombeResultsDetail_Read()
>>>>> Dim sLine As String
>>>>> Line Input #Last, sLine
>>>>> Print "SO=" & sLine
>>>>> DetailTextArea.Text &= sLine & "\n"
>>>>> Wait
>>>>> End
>>>>>
>>>>> It still did not clear the displayed contents of those controls. I
>>>>> clicked the button once (i.e. when the contents were already clear) and
>>>>> it populated the above controls as expected. I clicked the button again
>>>>> but it did not clear the DetailTextArea or the ListBoxes immediately.
>>>>> The CL program took a few seconds to run and interestingly when it
>>>>> finished it did not add to the controls' contents (i.e. it cleared them
>>>>> before populating them again).
>>>>>
>>>> Yes, that's precisely what the code above is meant to do, right? First you
>>>> clear all the controls, then you start an external process to fill them
>>>> anew. If you don't want to refill the controls, don't start the external
>>>> process which gives you the new data.
>>>>
>>>> In case I'm misunderstanding here, the best practice seems to me to be:
>>>>
>>>> [ 0. don't top-post, ]
>>>> 1. send a *small* project which shows your problem (with one or two
>>>> controls to clear and a call to "ls" or something),
>>>> 2. tell me exactly what you want to achieve
>>>>
>>>> and I'll send you the corrected project, if I can accomplish it.
>>>>
>> Tobi & Fabien,
>>
>> Bottom posting as requested. Project named Test attached: stripped down
>> from original project. I want the DetailTextArea to be cleared
>> onscreenimmediately when a second or subsequent Run is done (i.e. the
>> Run button is clicked twice). When the Run button is clicked it causes
>> the execution of 2 CL programs: create_menu & turing_bombe_all_wheels -
>> the second one taking 10+ seconds to execute. Currently the
>> DetailTextArea is only cleared onscreen when the turing_bombe_all_wheels
>> has finished executing.
>>
> Apparently you need to give it a little time:
>
> DetailTextArea.Clear()
> Wait 0.1
>
> works for me.
>
>> Fabien,
>>
>> You say "And th?? controls Will not be cleared until the procedure is not ended.Use an ascyncronous call to your external program can help you.". In Gambas, how do make an asynchronous call to an external program? I do not want to amend the coding in the external program turing_bombe_all_wheels. Current coding:
>> pturing_bombe = Exec ["/opt/Enigma/turing_bombe_all_wheels", sMenuPath] Wait For Read As "TuringBombeResultsDetail"
>>
> This would be best I think. Remove the "Wait" from your Exec line and you
> have an asynchronous process. This works here, too, and doesn't require a
> rule-of-thumb "Wait 0.1".
>
> Also, since you use the Process' Read event your code is essentially doing
> asynchronous reads of the process output. You force it artificially to be
> synchronous by using the Wait flag.
>
> A patch with both ways is attached.
>
> Regards,
> Tobi
>
>
>
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Tobi,
Thanks for the ideas. I amended the coding to:
pturing_bombe = Exec ["/opt/Enigma/turing_bombe_all_wheels", sMenuPath]
For Read As "TuringBombeResultsDetail"
Do
Wait 0.1
Loop Until pturing_bombe.State <> Process.Running
and it cleared the DetailTextArea OK on doing the second & subsequent
runs. I found that I no longer need the 'Wait' after 'DetailTextArea.Clear'.
PS Not on this topic, but when sending a tar.gz (e.g. of a gambas
project) using my gmail account, Google comes up with an email pointing
to one of their web pages stating that they prevent sending on of emails
containing attached .gz files (and .zip etc). That's why I previously
changed my attached files from .gz to .xyz. Another nuisance. courtesy
of Google, due to Windoze viruses!
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