Error HRESULT E_FAIL has been returned from a call to a COM component

Question

In Silverlight 4 app; what does this error mean?:

\"Error HRESULT E_FAIL has been returned from a call to a COM component.\"

It

Answer 1

In my situation:

I create a

class MyControl : ContentControl {
}

By default, the class is not public and XAML cannot load it and throw exception

Error HRESULT E_FAIL has been returned from a call to a COM component

Just change the scope of class to public and error disappear.

Hope this help.

PS. Microsoft should provide more on information than just throw a mystery error message without any stack trace.