Changes between Initial Version and Version 1 of Raise

Timestamp:

05/02/10 14:38:03 (15 years ago)

Author:

hopscc

Comment:

--

Raise

@@ +1 @@
+= Raise = 
+
+Trigger an event to fire with the specified args.
+
+If the event is not null and  any handlers are listening (registered with) [[BR]]
+the event they will be invoked after the event has been raised.
+
+See also [wiki:Listen] and [wiki:Ignore].
+
+== Grammar ==
+{{{
+raise <event> [ [,<source>] ,<event-args>]
+}}}
+
+If the <source> is not specified but <event-args> is, then '''this'''
+will be implicitly passed as the source.
+
+If an event has been declared with a no param signature 
+then neither <source> nor <event-args> can or need be given 
+as args to the raise call.
+{{{
+sig NoArgEventHandler                    # no parameters
+event notifyEvent as NoArgEventHandler   # is public
+...
+raise .notifyEvent
+}}}
+
+== Examples ==
+{{{
+use System.Windows.Forms
+
+...
+        button = Button(parent=p, autoSize=true, text='One', tag=1)
+        # connect event and handling code
+        listen button.click, ref .clickHandler
+        ...
+        # trigger the button programatically
+        raise button.click, EventArgs()
+        ...
+        # disconnect event and its handling code
+        ignore button.click, ref .clickHandler
+...
+def clickHandler(source as Object, args as EventArgs)
+    pass
+}}}
+
+
+Full example with augmented !EventArg, signature and event declarations, 
+convenience method to raise the event, event handlers/listeners
+{{{
+
+# EventArgs subclass to pass additional info in args
+class BEventArgs inherits EventArgs
+        var _value as int
+
+        get value from var
+        
+        def init(val as int)
+                base.init
+                _value = val
+
+# delegate for ActionEvent  <eventName>EventHandler
+sig ActionEventHandler(sender as Object, args as EventArgs)
+
+class Generator
+        var _count = 0 
+            """local state"""
+        
+        # event dcl for event called Action
+        # event <eventName>Event as <sigName> (<eventName>EventHandler)    
+        event actionEvent as ActionEventHandler
+
+        # (protected) method to raise/fire the event for this class 
+        # {on,fire}<eventName>Event
+        def _onActionEvent(args as EventArgs)      # fireActionEvent
+                raise .actionEvent, args
+
+        def bump
+                _count += 1     
+                if _count % 20 == 0
+                        ev = BEventArgs(_count)
+                        _onActionEvent(ev)
+
+class Listener
+        # the event handler method do<eventName>
+        def doAction(source as Object, args as BEventArgs)
+                print 'Event from [source] - argCount is [args.count]'
+            
+...
+class RaiseDriver
+        def main is shared
+                g = Generator()
+                l = Listener()
+                
+                #tie the generator event to the Listener method
+                listen g.actionEvent, ref l.doAction
+
+                for i in 100
+                    g.bump    
+
+                #untie the event and listener
+                listen g.actionEvent, ref l.doAction
+}}}
+
+No Arg event, No args passed to raise.
+{{{
+# delegate with no args for notifyActionEvent  <eventName>EventHandler
+sig NoArgEventHandler
+
+class Generator
+        var _count = 0 
+            """local state"""
+        
+        # event dcl for event called Action
+        # event <eventName>Event as <sigName> (<eventName>EventHandler)    
+        event notifyActionEvent as NoArgEventHandler
+
+        # (protected) method to raise/fire the event for this class 
+        # {on,fire}<eventName>Event
+        def _onNotifyActionEvent
+                raise .notifyActionEvent
+
+        def bump
+                _count += 1     
+                if _count % 20 == 0, _onNotifyActionEvent
+
+class Listener
+        # the event handler method do<eventName>
+        def doNotifyAction
+                print 'NotifyAction Event received'
+            
+...
+class RaiseDriver
+        def main is shared
+                g = Generator()
+                l = Listener()
+                
+                #tie the generator event to the Listener method
+                listen g.notifyActionEvent, ref l.doNotifyAction
+
+                for i in 100
+                    g.bump    
+
+                #untie the event and listener
+                listen g.notifyActionEvent, ref l.doNotifyAction
+}}}
+
+
+== Notes ==