Ticket Q373555

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Custom PropertyEditor based on ASPxListBox loses values

Krzysztof Krzyzsłof

created 12 years ago

I've been trying to make ASPxListBox work which would function correctly with the confirmation rules mechanism from the ticket:
http://www.devexpress.com/Support/Center/Question/Details/Q473947

Could you please see the WebCheckedListBoxEnumPropertyEditor (my target functionality) and/or FromString_ListBoxPropertyEditor (a little simplified one) in my updated project?
Both of them get cleared whenever you empty the 'Opis' field and click Save.

I found such information: http://www.devexpress.com/Support/Center/p/Q303458.aspx
Maybe it would solve the issue and be integrated in XAF somehow ?

I am sorry to ask you one more time for the similar issue.

SampleProj...nRules.zip

Show previous comments (2)

Dennis Garavsky (DevExpress) 12 years ago

I made your FromString_ListBoxPropertyEditor default for strings, but could not see the problem in my tests. Please refer to the attached video. Can you please provide me with the exact repro for your project?

Q373555.swf

Krzysztof Krzyzsłof 12 years ago

In order to reproduce the issue, you need to break some confirmation validation rule. Then browser confirm dialog appear - you need to confirm it in order to cause a callback with ObjectSpace.CommitChanges().
To simplify things I send an updated project where you can reproduce the issue more easily.
- in runtime set the Status field to "Rejected project"
- Save
[issue reproduced: all lists got cleared]

SampleProj...nRules.zip

Dennis Garavsky (DevExpress) 12 years ago

Thanks for the sample. I will convert it to 12.2 and test as soon as I can.

Krzysztof Krzyzsłof 12 years ago

I really need this functionality. Could you please try to solve/workaround this issue?
Thanks, Krzysztof

Dennis Garavsky (DevExpress) 12 years ago

Yes, I checked it, but I am still working on a solution, because working with custom editors usually requires more time than normally + the custom validation you implemented is quite complex as well. I hope to get back to you by the end of this day with my latest results.

Answers approved by DevExpress Support

Dennis Garavsky (DevExpress)

created 12 years ago (modified 12 years ago)

Hello,
Modify your code as follows:

C#
private void listBox_SelectedIndexChanged(object source, EventArgs e)  
{  
    if (Editor.SelectedItems.Count > 0) {  
        EditValueChangedHandler(source, e);  
    }  
}

I should mention that this may be not the last problem with the custom validation solution you implemented and this custom editor.
UPDATE:
In fact, my previous solution was rather a workaround than a real solution (it does not work if the items are unchecked), because we could not find a good way to avoid the situation when the listBox_SelectedIndexChanged method is triggered and indirectly calls the GetControlValueCore method.
The problem is that this is all triggered by your custom confirmation script that causes a callback to the server and calls the ProcessAction (which commits data!) at the moment when this data is empty. I already discussed this issue with our ASP.NET team and it looks like there is no way to avoid the listBox_SelectedIndexChanged call when the post data is loaded. So, it looks like this particular scenario is not currently supported in XAF, unless you found a way to implement a custom selection cache (e.g., store selected values in the ASP.NET session) and maintain it valid between callbacks. Probably, using another confirmation method, e.g. a regular XAF popup View (e.g., use a solution from How to invoke a View without using Actions or from a place that is different from the Controller context or rather register a script that will show the ASPxPopupControl window directly) will help you avoid this problematic situation, but I have not tested it yet and I cannot guarantee that it will solve the problem - these are just my suggestions on what else you can try in this situation, because we do not have a proper solution at the moment.

Show previous comments (5)

Krzysztof Krzyzsłof 12 years ago

Dennis, thank you for the answer.
I have checked it and it only partially solves the problem of clearing fields.
When I select some values on listbox, all's go OK.
However, when I deselect all values on listbox - then the state isn't saved.

Krzysztof Krzyzsłof 12 years ago

I have noticed that the custom PropertyEditor is created only once - when entering edit mode.
On the other hand, the methods SetupControl() and CreateEditModeControlCore() are created many times.
So I tried to persist the listbox selection in a class field:
ListEditItemCollection items;
and copy the selection to that field in SetupControl() method:
if (items != null) {
     foreach (ListEditItem item in editor.Items) {
          item.Selected = IsSelected(FindItem(items, item.Value));
     }
}
items = editor.Items;
The selection is copied correctly then.
BUT after confirming the browser dialog (that cause a callback with ObjectSpace.CommitChanges())
the listBox_SelectedIndexChanged() and editor_ValueChanged() are fired and selection gets cleared.
I have no idea when exactly does it happen and how to fix it.

SampleProj...nRules.zip

Dennis Garavsky (DevExpress) 12 years ago

Thank you for the update, Krzysztof. I missed this scenario yesterday.
In fact, my previous solution was rather a workaround than a real solution, because we could not find a good way to avoid the situation when the listBox_SelectedIndexChanged method is triggered and indirectly calls the GetControlValueCore method.
The problem is that this is all triggered by your custom confirmation script that causes a callback to the server and calls the ProcessAction (which commits data!) at the moment when this data is empty. I already discussed this issue with our ASP.NET team and it looks like there is no way to avoid the listBox_SelectedIndexChanged call when the post data is loaded. So, it looks like this particular scenario is not currently supported in XAF, unless you found a way to implement a custom selection cache and maintain it valid between callbacks. Probably, using another confirmation method, e.g. a regular XAF popup View will help you avoid this problematic situation, but I have not tested it yet.

Krzysztof Krzyzsłof 12 years ago

You mean to use a regular XAF popup View instead of a browser dialog, yes?
In the confirmation rules mechanism I use a browser dialog because I have to invoke it synchronously.
Is there a way to invoke a XAF popup view synchronously?

Krzysztof Krzyzsłof 12 years ago

Or maybe I would better store the propertyEditor's values in a System.Web.HttpContext.Current.Session .

Dennis Garavsky (DevExpress) 12 years ago

Yes, you can try to display a View as shown in the How to invoke a View without using Actions or from a place that is different from the Controller context KB Article or use a custom cache, probably stored in the ASP.NET session.
Alternatively, you can register a script that will show the ASPxPopupControl window directly. As I mentioned above, I cannot guarantee that it will solve the problem - these are just my suggestions on what else you can try in this situation, because we do not have a proper solution at the moment.

Krzysztof Krzyzsłof 12 years ago

Thank you - I will inform you about my results.
We release a new app. version on Monday so I will need to temporarily use your simple workaround.
Hopefully I will manage to fix it next week.
Thanks once again and have a nice weekend, Dennis!

Dennis Garavsky (DevExpress) 12 years ago

Thanks for the feedback, Krzysztof. I have updated my original answer to mention the latest considerations.

Created: April 11, 2013 4:49 PM

Modified: April 19, 2013 12:01 PM

Platform: App Frameworks (UI, API, ORM)

Product: XAF - Specify UI Platform

Build: 12.1.10

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Custom PropertyEditor based on ASPxListBox loses values

Answers approved by DevExpress Support

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