C1.Win.Editor (.NET 8) – Drag & Drop events not firing and document not loading

C1.Win.Editor (.NET 8) – Drag & Drop events not firing and document not loading

Posted by: andrea.davoli on 16 January 2026, 4:36 am EST

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  andrea.davoli

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  Posted 16 January 2026, 4:36 am EST

  Hello,
  
  I’m migrating a WinForms application from C1.Win.C1Editor to the new C1.Win.Editor on .NET 8 and I’m facing two major blocking issues. Documentation seems very limited, so this is based on testing.

  Environment
  
  • WinForms
  
  • .NET 8
  
  • C1.Win.Editor.C1Editor + C1EditorRibbon

  1. Drag & Drop events not firing (main issue)
     
     Drag & Drop into the editor appears to work (text is inserted), but:
     
     • C1Editor.DragDrop never fires
     
     • DragEnter fires inconsistently
     
     • Other events like MouseUp never fire
     
     • AllowDrop is set to True

  This prevents us from intercepting or post-processing dropped content, which worked correctly with the old editor.

  Question:
  
  Is standard WinForms Drag & Drop unsupported or limited in the new WebView2-based C1Editor?
  
  Is there an alternative event or recommended approach?

  2. Document not loading on form load
     
     When loading an existing document at form startup:
     
     • The load method runs without errors
     
     • The document is not actually loaded
     
     • Calling the same method again after the form is shown works
     
     I tried moving the load logic to the editor’s initialization/ready event, but the issue persists.

  Question:
  
  What is the correct lifecycle event to wait for before loading a document into C1Editor?

  2. Old DocumentChanged event missing.
     
     Is there an alternative method to the old DocumentChanged event to catch changes in the editor?

  Any guidance or best practices for handling these scenarios would be greatly appreciated, especially regarding WebView2-related limitations.
  
  Thank you.

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  kartik.dua

  

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  Posted 19 January 2026, 9:31 am EST

  Hi,

  Apologies for the delayed response.

  Regarding points (1) and (3), we were able to observe the behavior you mentioned related to the drag-and-drop events and the missing DocumentChanged event. We are getting in touch with the development team to get their insights and will share an update as soon as possible.

  Regarding point (2), the recommended approach to load a document in C1Editor at startup is by using the C1EditorReady event. Please refer to the attached sample project, which works as expected on our end. If you are encountering the issue with a different implementation, could you please update the sample project to reproduce the issue? This will help us investigate further and provide more accurate assistance.

  Attachment: C1EditorCore.zip

  [Internal Tracking ID: C1WIN-34926]

  Best Regards,
  
  Kartik

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  andrea.davoli

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  Posted 20 January 2026, 12:44 pm EST

  Hello,

  I’ve done further testing with the C1EditorReady event to load a document when the form opens, but still no results. I’m attaching a zip file containing a small WinForms NET8 example project.WinFormsAppTest.zip

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  kartik.dua

  

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  Posted 21 January 2026, 9:49 am EST

  Hi,

  Thank you for sharing the sample project.

  It appears that this behavior is caused by the control flow between when the C1EditorReady event is fired and when the C1EditorRibbon is attached to the C1Editor through the designer code. This flow seems to reset the contents of the C1Editor and start a new document.

  To resolve this, we recommend handling the C1EditorReady event in code after the InitializeComponent method has completed, ensuring that the C1EditorRibbon has already been initialized and the document is loaded afterwards.

  Please refer to the updated sample project for reference - WinFormsAppTest_Updated.zip

  Best Regards,
  
  Kartik