Controls
FoundationDelegate
An object encapsulating a reference to a method on another object.
- Object
- Delegate
Remarks
This class provides an easy way for creating an object that
can be used to call a method on another object.
Methods
| equals | Tests if two delegates refer to the same method. |
| invoke | Invokes the delegate. |
| invokeAfter | Invokes this delegate after a delay. |
| invokeOnIdle | Invokes this delegate just before returning from the current event handler. |
Delegate equals method
Tests if two delegates refer to the same method.
JavaScript
var boolVal = delegate.equals(otherObj)
Returns
true if otherObj is another Delegate instance pointing to the
same method this delegate points to. false otherwise.
Delegate invoke method
Invokes the delegate.
JavaScript
var obj = delegate.invoke()
Remarks
This method invokes the encapsulated method function on the
object passed in to the delegate constructor.
Returns
The value returned by calling the function, or
undefined
if the function returns no value.Example
To create a delegate, use:
var d = new Delegate(myObject, MyClass.prototype.methodName);
The object in d is now an alais for myObject's methodName method.
i.e. writing:
d.invoke();
is then equivalent to writing:
myObject.methodName();
Delegate invokeAfter method
Invokes this delegate after a delay.
JavaScript
var obj = delegate.invokeAfter(delay)
Remarks
Call this to invoke this delegate object asynchronously after a wait of
delay milliseconds.
Returns
A JavaScript object which has a cancel() method that can
be used to cancel the invokeAfter.
Example
This invokes the myPopup function after a second:
function myPopupFunc() { alert('hello'); }
var delegate = new Delegate(null, myPopupFunc);
delegate.invokeAfter(1000);
You can save the result returned by invokeAfter and use it to cancel the
delayed action:
function myPopupFunc() { alert('hello'); }
var delegate = new Delegate(null, myPopupFunc);
var t = delegate.invokeAfter(1000);
t.cancel(); // cancels the invokeAfterDelegate invokeOnIdle method
Invokes this delegate just before returning from the current
event handler.
JavaScript
delegate.invokeOnIdle()
Remarks
Used to invoke the delegate on the next idle.