Order of new row problem after save and then cancelChanges

[Salim]

Check the following scenario:

1. Go to the following example: http://dojo.telerik.com/uVInI

2. Add new row, enter its data, and click "Save"

3. Click "Cancel"

 

The new row which was the first one is now the last one. The "cancelChanges" should not affect the order of the new row

[Alex Hajigeorgieva]

Hello Salim,

Thank you very much for the provided runnable demo. 

This behaviour is expected if you follow the logic in the cancelChanges()  method you will see that the data is assigned back to the _pristineData:

https://github.com/telerik/kendo-ui-core/blob/master/src/kendo.data.js#L2841

In the depicted scenario, there are no changes and the _pristineData holds the items sorted with the newest item at the end of the data source data array. When a subsequent read is requested, the server responds with the dataItems ordered by their creation in descending order. 

There are several options to prevent this and in your scenario, the easiest one is to check for changes. If there are no changes, do not call the cancelChanges()  method:

http://docs.telerik.com/kendo-ui/api/javascript/data/datasource#methods-hasChanges

For your convenience, I have updated the demo at:

http://dojo.telerik.com/uVInI/2

Regards,
Alex Hajigeorgieva
Telerik by Progress

[Salim]

This is a wrong behavior since you are providing an option for the new row to be on top or at the bottom. So, the _pristineData should set the priority of the new based on the position of the new row

[Alex Hajigeorgieva]

Hi Salim,

You seem to have a valid point regarding the expected behaviour when cancelling changes. However, please note that to ensure that the data is sorted, you should add a sort configuration or implement your own method of comparison:

http://docs.telerik.com/kendo-ui/api/javascript/data/datasource#configuration-sort.compare

For your convenience, I have updated the demo to compare by ProductIDs:

http://dojo.telerik.com/UGOko/2

I hope this helps.

Regards,
Alex Hajigeorgieva
Telerik by Progress