Question

I found a method here on stack overflow that strips all event handlers from a given event. However, when I copied the code into my program it gave me a “Reference not set to an instance” error.

Here is the code in question:

        FieldInfo f1 = typeof(Control).GetField("DocumentCompleted",
        BindingFlags.Static | BindingFlags.NonPublic);
        object obj = f1.GetValue(browser);
        PropertyInfo pi = browser.GetType().GetProperty("Events",
        BindingFlags.NonPublic | BindingFlags.Instance);
        EventHandlerList list = (EventHandlerList)pi.GetValue(browser, null);
        list.RemoveHandler(obj, list[obj]);

The error happened on this line:

object obj = f1.GetValue(browser);

The browser object is an instance of WebBrowser, and it has been instantized at this point.

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Edit: Came up with a different way of removing the handlers.

Answer 1

DocumentCompleted is a public event, not a private static field, so f1 is null and cause your error