c# - Cannot inherit from event args class: no contructor?

Question

I'm using WebClient in a .NET 4.7.2 WinForms application. I calling the UploadProgressChanged event, which receives an UploadProgressChangedEventArgs object. I'd like to add a extra property to the event args, so I'm trying to extend UploadProgressChangedEventArgs as UploadProgressChangedExtEventArgs.

    public class UploadProgressChangedExtEventArgs : UploadProgressChangedEventArgs {
        public UploadProgressChangedExtEventArgs() { }
    
        public string Message { get; set; }
    }

However, I get the error "CS1729: 'UploadProgressChangedEventArgs' does not contain a constructor that takes 0 arguments."

According to the documentation (and Object Browser seems to support this) UploadProgressChangedEventArgs doesn't have a constructor -- like, at all -- though it's base object ProgressChangedEventArgs does. I've tried using base() to supply the arguments to the ProgressChangedEventArgs constructor, but then I get "does not contain a constructor that takes 2 arguments" error.

Am I just not able to inherit from UploadProgressChangedEventArgs object? Is this a bug in .NET? Am I missing something obvious?

question from:https://stackoverflow.com/questions/66048209/cannot-inherit-from-event-args-class-no-contructor

Answer 1

Waitting for answers