Pushing the object within the object question

My end goal is to be able to write the following code and have it work for reading data into and out of the object (Ptr2FieldData). I should point out that Coordinates is a property of Ptr2FieldData and is an object.

Ptr2FieldData.Coordinates.X

Here is what I am currently doing which is a step in the right direction, but does not get me to my goal. Thanks to xlNitWit, the code works:

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But if I attempt to consolidate the code, the compiler complains with error ‘91’ object variable not set. I know I must be misunderstanding something….please offer insight.

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Here is a shortened Ptr2FieldData Class containing only the critical Coordinate Property

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And here is the CoordinatesClass

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Hi xlNitWit!

thank you for replying.

You stated that "IF YOU HAVE NOT ASSIGNED A COORDINATECLASS object to the property, you cannot write to that object's properties.

I thought I had done that. Look at "MeasurementClass" which is the class I used to instantiate Ptr2FieldData. I assign Coordinates as a CoordinateClass using the "set" instruction you told me about in the earlier question.

Am I missing something? Remember I am a novice so if you can readily see my mistake and I can not, please be patient.
thank you,

bil

Ok, xlNitWit.....I think I am understanding you. I apologize for taking so long.
As you know I am 72 and so sometimes I am not intellectually all there. Sorry.

If I am understanding you correctly,the first piece of code
explicitly declares(Dim) and instantiates(new) a
FieldDataCoordinates object. Also, a pointer (reference) to
that object is defined (set).

The FieldDataCoordinates property,X, expects a double to be
storied in it. That data type is the data type found in the
appropriate worksheet cell. The FieldDataCoordinates object
is filled with data via the equals sign.

That declared and instantiated and filled object,
FieldDataCoordinates, can then be written into the Coordinate
property of the Ptr2FieldData object which expects at least
a declared and instantiated object for that property.

I think that just about wraps up my understanding of your explanations on
how I could get my code to work.



You asked me why I simply did not use the working code I already had in place.

The big picture answer is this:
* the code as originally written encapsulates Ptr2FieldData in a clear fashion.
It holds:
* a measurement ID of type long
* a measurement elevation of type double
* a measurement type of type string
* measurement coordinates of type object
each of the above properties were intended to be the major categories of any
Ptr2FieldData object.

*But with your help, I began to appreciate that if a property is going to be
an object, that object has to be declared and instantiated EXTERNAL to the
Ptr2FieldData object.

That means I lose encapsulation. I place a burden on the code using the
Ptr2FieldData object to not only know something about coordinates.but to also
include code necessary to use it (declare and instantiate code)

So my question was really about trying to find a way around this dilemma.

Encapsulation of high level abstractions (as represented by an object) necessarily
shifts knowledge of lower level abstractions that will make up the higher level
abstractions to the code using the high level abstractions.

It seems if I want to preserve encapsulation, I need to make an object interface
take in the lowest abstraction level information and output the highest level info.

any ideas?