Public Shared Event ThreadPreprocessMessage As ThreadMessageEventHandler

Dim handler As ThreadMessageEventHandler

AddHandler ComponentDispatcher.ThreadPreprocessMessage, handler

public static event ThreadMessageEventHandler ThreadPreprocessMessage

public:
static  event ThreadMessageEventHandler^ ThreadPreprocessMessage {
    void add (ThreadMessageEventHandler^ value);
    void remove (ThreadMessageEventHandler^ value);
}

JScript does not support events.

You cannot use this event in XAML.