Hello everybody,
I have finally decided to learn xojo. My programming background is nearly zero and so is my OOP know how.
In my app I created a class A that holds some methods and properties.
I would like to create an object from class A at the start of the application and the object should live as long as the application is running.
Tried to define a variable in the app open event
Dim myObject as new A
and as expected myObject is available with its methods, but outside the open event it is not.
On the other hand, creating a property at app level seems to work and app.myObject is available everywhere.
My questions:
how should I create an object that must be reachable from “everywhere” correctly?
what is the difference between variable and property?
As a side note: yes, I searched, but I did not found anything helpful (that I could understand).
[quote=434909:@Thomas Zenker]Hello everybody,
I have finally decided to learn xojo. My programming background is nearly zero and so is my OOP know how.
In my app I created a class A that holds some methods and properties.
I would like to create an object from class A at the start of the application and the object should live as long as the application is running.
Tried to define a variable in the app open event
Dim myObject as new A
and as expected myObject is available with its methods, but outside the open event it is not.[/quote]
Well you’d expect that too. myObject is a local variable. Local, that is, to the open event handler. It dies when the handler completes. If you want it to be available elsewhere, create it as a property of a window, f’rinstance. You’d still need to initialise it of course.
A variable is a something that is "Dim"ed in a method or event. It is local to that context and not available elsewhere. A property is similar to a variable, but is defined as part of an object. (App is an object, as is Window1.) It may also be part of a Module. A variable is created by you explicitly in the Dim statement. A Property is created by the system as part of the creation of the object.
