Capture Drag Event of Node causes render to fail about blazor.diagrams HOT 5 CLOSED

Hi @antwjadam,

Defining additional parameters (including event handlers) to nodes is generally not supported. You can get updates to the node positions by binding to their coordinates. That way, the property you're binding to is always kept up-to-date.

BR
Stefan

from blazor.diagrams.

Yup, I have the binding to the co-ordinates, so that when retrieving my node list from the db, the diagram draws correctly. What I need though is to catch the event that the node on the diagram is dragged to a new position, The diagram rendered is showing the node in the new position fine, the x,y bindings give the new co-ordinates fine. But I need to trigger an update to the database to update the co-ordinates on the database record for that node.... something like in pseudo code

... node has moved event is triggered (this is the thing I cant work out - how to detect the change)
... get the new x,y from the bound values
... using the node id, find the node record on the database for that id (I can do this bit)
... update the x,y on the database to the new values (this is easy)

I did notice the selection change event triggers when clicking on the node to start dragging it, and fires again when releasing the node in its new position, so I though I could maybe using the reference to the diagram, step through all the nodes looking for x,y updates needed to be done on the db.

from blazor.diagrams.

I see. While you can technically just modify the bind to perform more operations on ValueChanged, I would advise against that, because it would fire for every tiny little change, even during the move. I'm working on a larger code refactoring of mouse interaction at the moment, so I'll have a look into adding such an event while I'm at it.

from blazor.diagrams.

Thanks!

At the moment, I am going to try this in my selection change event (its a bit sledge hammer to crack a nut but will get me what I need for now)

// all nodes deselected so check for x,y change
foreach (var nodeRendered in diagramNodes)
{
var nodeDatabase = nodesService.GetNodeById(nodeRendered.Id);
if (nodeRendered.X == nodeDatabase.X && nodeRendered.Y == nodeDatabase.Y) continue;
nodesService.UpdateNodeXY(nodeRendered.Id, nodeRendered.X, nodeRendered.Y)
}

from blazor.diagrams.

This is now part of v3.12.0: You get a OnModified event callback on the Nodes. Please let me know in case it doesn't work for you.

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