Undo Question - How to find actual deletedItems, not just their names

[Jim Jacobs]

Hi,

I'm starting to play with Undo/Redo again and have a question.
If I select multiple nodes and click on delete, in my historychange event handler I see the following:

args
  > changes
    > 0
      > deletedItems
        > 0
          > _type  "pseudoGroup"
          > children
            0   "TaskQTqu"
            1   "Data-StorewrAU"
            2   "InterProcessRtfo"

I have also attached a screenshot showing a slightly different, but similar, scenario.
Where can I find the actual nodes that are being deleted?
I need to interrogate various addInfo properties of these nodes.
Using diagram.getNode("TaskQTqu") does not return the node (since it's no longer on the diagram).

Obviously the node info is stored somewhere since I am able to Undo the delete and the addInfo properties are restored.

How can I locate the node info?

Thanks

Jim





Attachment: Undo__deletedItems_for_selection__05apr2017_bea7ec41.zip

[Shyam G]

Hi Jim, 

 

Please use nodeCollectionChange event to achieve your requirement. While performing undo operation, the nodeCollectionChange event triggers if an collection is modified. In this event, you can get an objects which is inserted or deleted.  

 

Code example: 

//define nodecollectionchange event 

DiagramContent.OnClientNodeCollectionChange = "nodeCollectionChange"; 

 

function nodeCollectionChange(args){             

                //we get an object only if a cause is historyChange 

            if (args.state === "changing" && args.cause === "historyChange") {                  

                //get an element 

                var node = args.element; 

                  

            } 

        } 

 

Regards, 

Shyam G 

[Jim Jacobs]

User Action	nodecollectionchange cause	nodecollectionchange changeType	historychange cause	What to do?
Drop new node	drop	insert	undefined	Add new node to database
Undo drop	unknown	remove	undo	Remove node from database
Redo drop	historychange	insert	redo	Add node to db with previous properties
Delete the node	unknown	remove	undefined	Remove node from database
Undo delete	historychange	insert	undo	Add node to db with previous properties
Redo delete	unknown	remove	redo	Remove node from database

Shyam,

Thanks for the tip.

It seems that if the nodecollectionchange changeType is remove, I cannot rely on the nodecollectionchange cause to determine if an undo or redo was just performed.

Instead I'm setting a global variable in the historychange event to indicate this action.

Is this correct?    Should the nodecollectionchange cause not be "historychange" if I do a redo?

Comments?

Thanks

Jim

[Shyam G]

Hi Jim, 

 

We considered this “Need to update missing cause in the nodeCollectionChange and historyChange event” as an issue and a support incident has been created under your account to track the status of this requirement. Please log on to our support website to check for further updates. 

 

https://www.syncfusion.com/account/login?ReturnUrl=/support/directtrac/incidents 

 

Regards, 

Shyam G