[Gambas-user] save and load an array of MydataType

[Jochen Georges]

Hello gambanauts,

I do not find a way on my own :(
I have an array wich is filled with objects of the class CCar.
I would like to save and load this array.
I found a way to do that if i know how much elements the array contains.
But I do not find a way, if I do not know how much elements the array 
contains.

------------------------------------------------------------
(The form has got two buttons (load and save) and a TextLabel)
arCars AS Object[]
cnt AS Integer

PUBLIC SUB _new()
    'make the array arCar with 3 objects of CCar in it
    i AS Integer
    DIM tmpcar AS CCar
    cnt = 3
    arCars = NEW Object[]
    FOR i = 0 TO cnt
        tmpcar = NEW CCar(Str(i))
        arCars.add(tmpcar)
    NEXT
END

PUBLIC SUB Button1_Click()
 'save it to an file
 ' I think i only save the CCar objects and not the array itself, do I?
    myFile AS File
    i AS Integer
    IF Dialog.SaveFile() THEN RETURN
        TRY OPEN Dialog.Path FOR CREATE AS myFile
            FOR i = 0 TO cnt
                arCars[0].writeTo(myFile)
            NEXT
        CLOSE myFile
END

PUBLIC SUB Button2_Click()
    i AS Integer
    myFile AS File
    newCars AS Object[]
    tmpcar AS CCar
    newCars = NEW Object[]
    FOR i = 0 TO cnt
        tmpcar = NEW CCar
        newCars.add(tmpcar)
    NEXT
    IF Dialog.OpenFile() THEN RETURN
        TRY OPEN dialog.Path FOR READ AS myFile
 'guess cnt is not constant and I do not know how much objcts of car are in
 ' the file:
 'how can I know at this point how much objects of CCar are in the file?
            FOR i = 0 TO cnt
                newCars[i].ReadFrom(myFile)
            NEXT
        CLOSE myFile
        TLb1.Text = Str(arCars[0].getBrand())  & 
  Str(arCars[1].getBrand()) &
  Str(arCars[2].getBrand()) 
END

I assume, that i have to write a class 
"MyOwnArrayWhichIsFilledWithCCarObjects"
this class needs a Method WriteTo.
And a set- and get Method for each set- and getMethod of CCar.
That does not seem to be elegant to me.

So, how would you do that?

Thanks for any hint.

Jochen