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Request a Feature Report a Bug
Unplanned
Last Updated: 27 Feb 2026 08:57 by ADMIN
Alexander
Created on: 26 Jan 2026 09:31
Category: Diagram
Type: Feature Request
4
Diagram OnConnectionCreated event

Current limitation: When DiagramShapeDefaultsEditable.Connect="true", users can draw connections between shapes, but there is no event fired when a new connection is created by the user.
Requested feature: Add OnConnectionCreated event that:

  • Fires when user creates a new connection by dragging from one shape to another
  • Returns event arguments containing:
    • FromShapeId — the source shape identifier
    • ToShapeId — the target shape identifier
    • Connection — reference to the newly created connection object (or its properties)
  • Allows developers to intercept, validate, or customize the connection before it's finalized

Use case: We need to capture user-created connections to persist them to database, validate business rules (e.g., prevent circular dependencies), and set connection properties (type, label, color) based on context.

2 comments
ADMIN
Dimo
Posted on: 27 Feb 2026 08:57

Hi Viorel,

Thanks for the detailed description of your use case.

Currently, this item is pending prioritization, and there is no set delivery date due to lower customer demand, compared to other requests. You can follow the feature request (if you haven't already) to receive status updates.

Regards,
Dimo
Progress Telerik

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Viorel
Posted on: 21 Feb 2026 10:02

We're building a workflow designer where users need to visually connect workflow states by dragging arrows between shapes. Currently, we have to use one of these workarounds:

Option 1: Polling with timer - Call SaveAsJsonAsync() every few seconds to detect new connections, but this:

  • Causes race conditions during save operations
  • Impacts performance with unnecessary polling
  • Makes the UX unpredictable

Option 2: Manual sync button - Users drag connections, then click a "Sync from Diagram" button to create the data models. This works but feels clunky compared to automatic detection.

The proposed OnConnectionCreated event would be perfect for our use case. We need to:

  • Create database records (WorkflowTransition) when users draw arrows
  • Validate business rules (e.g., prevent duplicate transitions, enforce state rules)
  • Auto-populate transition names based on connected states

When is this feature planned for release? This would significantly improve the Diagram component's usability for workflow/process designers.

Thanks!

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