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RichTextEditor issues

info

This control is available as part of Avalonia Pro or higher.

For reference information on this control, see the RichTextEditor page.

Document is null​

Ensure you have set the FlowDocument to be accessed by the editor.

if (editor.Document == null)
{
    editor.Document = new FlowDocument();
}

Undo does not work​

Ensure you have created an UndoManager in your code-behind.

editor.Document.TextDocument.UndoManager = new UndoManager();

Edits do not appear in the editor​

Try wrapping multiple operations as a batch edit.

doc.BeginChange();
try
{
    // Your edits
}
finally
{
    doc.EndChange();
}

Debugging threading issues​

Enable thread assertions​

Avalonia has built-in thread checking:

// Throws if not on UI thread
Dispatcher.UIThread.VerifyAccess();

Common exceptions​

InvalidOperationException: "The calling thread cannot access this object because a different thread owns it."

  • Cause: Accessing UI thread object from background thread
  • Fix: Use Dispatcher.UIThread.InvokeAsync()

NullReferenceException when accessing Element

  • Cause: Weak reference collected or background thread access
  • Fix: Check null and ensure UI thread

I need help with something else​

See also​

On this page