Copying an Instance of a Class

General
42

What glitch ? Should work.

And I never instantiated a class in-line in Xojo thinking it does not work because when I tested:
Msgbox (new Date(2014,8,1,23,59,59)).SQLDateTime // Got a compiler Error

Never thought that recasting a Date to a Date would make it work: Msgbox Date(new Date(2014,8,1,23,59,59)).SQLDateTime

Class myClass

        Public theData As Integer = 123

        sub Constructor( )
        end sub

        Function Clone() As myClass
               Dim c As New myClass
               c.theData = theData
               Return c
        End Function

        Function DestructiveTest() As integer
              theData = 0
              Return doAWeirdThingsReturningAnInteger(self)
        End Function

End class
  
Dim a As New myClass  // a.theData = 123
msgBox Str(a.Clone().DestructiveTest()) // Should return an integer status obtained from a copy of the object
                                         // whose contents where modified, but this copy was just discarded after.
MsgBox str(a.theData)  // Still 123
43

I have a working Serialization class and Clone method. It works for deep cloning. I’ll give you a project you can use when I get the chance.

44

MethodExtender2014-07-31.zip

A few things to note about the serialization/cloning

  1. It currently does not handle circular references.
  2. It currently does not support multi-dimensional arrays (My understanding as this is currently a limitation of introspection with XOJO)
  3. All objects serialized/cloned must have a public constructor that takes no parameters

Use:

  dim myObject as new myClass()
  dim myClone as myClass =   myClass(myObject.Clone)

If you want to add this to your own project you will need the Serialization Class and the Clone Method copied into your project.

Just a warning. There are a few other incomplete classes in this project. One is working on a Xojo Entity Framework for databases and another to do linq like expressions.

45

Right - its a glitch that it DOESNT

Right - there are some interesting things (like this that are / were intended to work that don’t)
Joes been working on a list of things that “should” work that don’t