How to filter collection properties

thanks Ivan
filtering seems to be working but the way it looks is not good - see attachment
if user adds 2 tokens separately he wants to see them in the same way and not displayed twice the same new token containing both
thanks,
Victor

I see that you introduced gridControl1_CustomColumnDisplayText which modifies every Token by joining all tokens in the column
this could not be a solution as then the whole Token approach is becoming not user friendly
thanks,
Victor

Thank you for your update. I didn't notice this side effect before. We have discussed this drawback with our developers and decided to fix it. I have created a new report about it - Tokens display wrong text when the CustomColumnDisplayText event is handled. We will update that thread once we have any news.
In the meantime, you can work around this issue by creating a ComboBoxEdit descendant - see the attached sample.

thanks Ivan - it works fine!
--
just a quick side note - the few requirements I had seem to be very basic:

1. tokens to be working in datagrid - probably the most widepspread of usage tokens
2. ability to have a unique list of tokens shared between rows in the grid - again very basic as typing tokens is error prone and normally is used only for a new ones
3. filtering on token column - without this token is quite useless for the grid
   and in order to have this basic functionality there is need for quite a lot of customization it seems
   so I wonder if Devexpress might consider providing it out of the box
   thanks again,
   Victor

Many thanks for your feedback, Victor. Although I cannot guarantee that filtering collection will be supported in the near future, I have passed your feedback to our developers. In the meantime, let me address the issues you mentioned.

As far as I understand, issues 1-2 were discussed in the T187964 ticket, where we suggested handling the PropertyChanged event. In newer versions, we provided a simpler way to synchronize ItemsSource of different editors that does not require handling events for all data source objects. Before I describe it, let me quickly explain why handling the PropertyChanged event was required.
An editor in the non-lookup mode (i.e., when DisplayMember/ValueMember property is not set) can display items that do not exist in the ItemsSource collection. I.e. when you enter a new item, it's not added to the ItemsSource.
Starting with version 14.2.8, you can set the editor's AllowRejectUnknownValues option to True and add an entered value to the source collection in the ProcessNewValue event handler. In this case, all editors will be automatically synchronized. I have modified your sample from T187964 to demonstrate this approach. Please take a moment to review it.

As for the issue with filtering, it's possible to accomplish your task without creating custom columns. You can also handle the ShowFilterPopup event and provide custom items there - we used this approach in the T214763 ticket. Perhaps, this approach will be more convenient in your scenario.

hi Ivan
thanks a lot on following up on my request!
I tried the solution and indeed so far it seems more straight forward. I didnt go as far as filtering as I see one problem which is not user friendly.
for AllowRejectUnknownValues to work I guess you set ValidateOnTextInput="False"
it has a side effect - if I enter a new token it appears in the list but it is not added to the column.
I need then to select it from the list which is not ideal behavior.  In the solution above (with PropertyChanged etc) Tokens are added immediately to the both the column and the conbobox.
Thanks,
Victor

It's strange, but I don't see this problem in the T187964_modified.zip project and my final T262755.zip project after applying my last approach. Please take a look at the attached screencasts. Would you please update my sample to show the problem?

hi Ivan
maybe it is an issue in 15 as I had to upgrade
please see screenshot before and after entering the the project upgraded
thanks,
Victor

dunno how to attach 2 at once

dunno how to attach 2 at once

Hello,
By default, in version 14.2, TokenComboBoxEdit's IncrementalFiltering property is set to "False". But in version 15.1, StyleSettings are set it to "True". To resolve this issue, you can set ComboBoxEdit's IncrementalFiltering property to "False". I have modified your sample project to demonstrate this approach.

Thanks,
Kirill

Thanks Kirill
I am changing what I implemented before using the approach suggested by Ivan with your comment.
So far it seems to be working and it easier than initial approach
Regards,
Victor

You are welcome!

hi Kirill, sorry for bothering you again but I see a new small issue with this implementation
if datacontext has some items with tokens populated while data initialization - these tokens behave very strange - they dont appear to start from (without AllowRejectUnknownValues="True"  they can be seen fine )
then they come up if I enter token="test1" in the second row
they can be seen as well if I double click on this cell
please see the solution
thanks,
Victor

Hello,
This issue occurs because the AllowRejectUnknownValues is set to "True". So, when you enter some new value and this value does not exist in ComboBoxEdit's ItemsSouce, you can handle the ProcessNewValue event. But if you manually assign ComboBoxEdit's EditValue, or it will be assigned in GridControl's cell, ComboBoxEdit will reject this value. That's why you cannot see it until you enter the same value in another ComboBoxEdit whose ItemsSource property is bound to the same collection. The easiest way to resolve this issue is to populate your DistinctTokens collection with the items you try to assign. You can do it at the same moment when you populate your Tokens collection with your items.

Thanks,
Kirill

thanks Kirill
I am looking how to do it properly in our solution
in meanwhile I found that Devexpress throws nullRefrenceException because of IncrementalFiltering ="False"
I didnt know initially that it was teh reason and created a separate ticket - please see
https://www.devexpress.com/Support/Center/Question/Details/T266874
regards,
Victor

of course if I remove it I am getting to the initial problem … :(

Hello Victor,

We have reproduced the problem with NullRefrenceException in the DXGrid control. This problem will be resolved in the ComboBoxEdit in a GridControl column raises an exception after upgrade to 15.1.4 ticket.

Thanks,
Elliot