public Interval Interval { get; protected set; }

<DxRichEdit @ref="@richEdit" />

@code {
    DxRichEdit richEdit { get; set; }
    @* ... *@
    /* Surround the code that contains an asynchronous operation with a try-catch block to handle
    the OperationCanceledException. This exception is thrown when an asynchronous operation is canceled. */
        try {
        @* ... *@
            // Find a bookmark by its name and get the bookmark's interval
            var bookmark = await richEdit.DocumentAPI.Bookmarks.GetAsync("chapter1Bookmark");
            if (bookmark != null) {
                var bookmarkInterval = bookmark.Interval;
            }
            @* ... *@
        }
        catch (OperationCanceledException e) {
            Console.WriteLine($"{nameof(OperationCanceledException)} thrown with message: {e.Message}");
        }
}