When an event occurs, I want to cause an undo.

[aim Systems]

When a connectionChange event occurs, even if the xy coordinate is arbitrarily changed, the connected connection cannot be disconnected.

 connectionChange: (args) => {

        let diagram = document.getElementById('diagram').ej2_instances[0];

        if(args.state == "Changed"){

          if(diagram.connectors.length > 3){

            args.cancel = true;

            diagram.selectedItems.connectors[0].sourcePoint.x = 0;

            diagram.selectedItems.connectors[0].sourcePoint.y = 0;

            diagram.selectedItems.connectors[0].targetPoint.x = 0;

            diagram.selectedItems.connectors[0].targetPoint.y = 0;

            diagram.dataBind();

          }

Can Connect connected to a node be disconnected and returned to its previous state?

or 

can i cause Undo?

[Sivaranjith Jeyabalan]

Hi,

We have fulfilled your requirement using the connection change event.

When we set 'cancel' to true in the 'changed' state of the event, the connector will not disconnect.

We can cancel the connection in the changing state and use the 'sourcePointChange' and 'targetPointChange' events to retrieve the connector's previous position and reset it.

Please find a sample and code example below.

Code example:

      sourcePointChange: (args) =>{

        if (args.state === "Start") {

          localStorage.setItem('sourcePoint', JSON.stringify(args.oldValue));

        }

      },

      targetPointChange: (args) =>{

        if (args.state === "Start") {

         localStorage.setItem('targetPoint', JSON.stringify(args.oldValue));

        }

      },    

 connectionChange: (args) => {

        if (args.state === "Changing") {

          let diagram = document.getElementById('diagram').ej2_instances[0];

            args.cancel = true;

            if(args.connectorEnd === 'ConnectorTargetEnd')

            {

              let newValue = JSON.parse(localStorage.getItem('targetPoint'));

              diagram.selectedItems.connectors[0].targetPoint.x = newValue.x;

             diagram.selectedItems.connectors[0].targetPoint.y = newValue.y;

            }

            else if(args.connectorEnd === 'ConnectorSourceEnd')

            {

              let newValue = JSON.parse(localStorage.getItem('sourcePoint'));

              diagram.selectedItems.connectors[0].sourcePoint.x = newValue.x;

              diagram.selectedItems.connectors[0].sourcePoint.y = newValue.y;

            }

            diagram.dataBind();

        }

      },

 

Attachment: connectionchangeevent_fc003820.zip