Variable declaration?

[KDR]

Okay, so I have a button on a form that starts off a data collection process. One of the first things that happens is that several SHARED variables are DIMmed and then assigned values (mostly logical False, but a few are blank character vars).

Three or four forms are called. Each one, in its INIT event, DIMs those shared variables again so that they can be used by the form. (I collect data to variables rather than directly enter data into a table in order to check the data and for other manipulation prior to placing the information into the record.)

My question is this: I originally used fields copied from a form that IS directly accessing/showing the data, and converted the source from a table/field to a variable. But it seems that the form doesn't see the variables that I DIMmed in the INIT event.

I have to create a "new" variable rather than assign an existing one to the data object. Am I doing something wrong?

[Stan Mathews]

Re: Variable declaration?

DIMmed in the INIT event

You may have a timing issue. Try dimming them in the onactivate event. (Follows the oninit timewise)

[KDR]

Re: Variable declaration?

Thanks, Stan. I'll give that a go first thing tomorrow -- leaving the office in less than a minute!

[KDR]

Re: Variable declaration?

Just got in and will be on this in a few minutes, but one question occurred to me. Does it matter if I choose "Create using Xbasic" or "Create using Action Scripting" as to whether or not the DIMmed variables will be visible for me to use when setting the properties of an object?

[Stan Mathews]

Re: Variable declaration?

No.

[KDR]

Re: Variable declaration?

Well, it didn't work.

Here's what I have in the OnActivate event for the form:

'Date Created: 05-May-2010 11:45:08 AM
'Last Updated: 05-May-2010 12:15:59 PM
'Created By : Kevin
'Updated By : Kevin
DIM SHARED varL_Schl_acc as L
DIM SHARED varL_HF_app as L
DIM SHARED varL_HF_agr as L
DIM SHARED varL_drv_pol as L
DIM SHARED varL_BG_chk_auth as L
DIM SHARED varL_BG_chk_conf as L
DIM SHARED varL_HF_int as L
DIM SHARED varL_HF_scrn as L
DIM SHARED varL_HF_refs as L
DIM SHARED varL_welcm_brch as L
DIM SHARED varL_HF_pre_o as L
DIM SHARED varL_HF_post_o as L
DIM SHARED varA_pcmt_cmnt as C

varL_Schl_acc = .F.
varL_HF_app = .F.
varL_HF_agr = .F.
varL_drv_pol = .F.
varL_BG_chk_auth = .F.
varL_BG_chk_conf = .F.
varL_HF_int = .F.
varL_HF_scrn = .F.
varL_HF_refs = .F.
varL_welcm_brch = .F.
varL_HF_pre_o = .F.
varL_HF_post_o = .F.
varA_pcmt_cmnt = ""

These are also DIMmed in the OnPush event of the button that, among other things, calls the form in question.

I want to use these variables in the Field property of several check boxes on the form. However, when I go to choose them they are not listed as available variables. I have to enter them again as new variables. I know I'm doing something wrong, I just can't figure out what that something is.

[Stan Mathews]

Re: Variable declaration?

Not sure exactly what you are trying to do. "Shared" has to do with available to other scripts on the same form, not shared between forms.

You may need to use global variables or get a session handle to which to refer.

[KDR]

Re: Variable declaration?

I'll make 'em global and see what happens.

[Stan Mathews]

Re: Variable declaration?

Then you may also want to change to the autoexec script for the form or the oninit event for your startup form. That way they will be available in the drag drop list when you design other forms.

You might also check this thread in the code archive. Dusty but serviceable.

[KDR]

Re: Variable declaration?

Actually, changing the autoexec script for the app was the first thing I did.

And, as you already knew, it worked perfectly.

I guess I need to do some more studying up on scope, as the fact that "Shared" only referring to scripts on the same form (rather than forms called by other forms) was not clear at all from what I've read so far. That one statement from you was far more illuminating than any other text I've read. Thank you!

I'll read the thread you linked to ASAP.

[Stan Mathews]

Re: Variable declaration?

I may not have expressed that correctly. See the screenshot for the explanation visible when defining variables for a form and using the Understanding Variable Scope link.

May be a question of understanding what a session is.

[KDR]

Re: Variable declaration?

May be a question of understanding what a session is.

I think that is the core issue, right there.

[MikeC]

Re: Variable declaration?

Here is an analogy I have used and just wrote down....maybe it will help in understanding....

Variable Scope:

An Analogy....been told by various individuals and modified for my own explanation

to people.

Think of a business in which the building is a warehouse that has offices inside it.

3 different cases:

1. The CEO, while IN his office with the door CLOSED, tells his secretary to do

something.
The only people privy to this conversation are the CEO and the secretary. (Local

variable)

2. The CEO, while IN his office with the door OPEN, tells his secretary to do

something.
The people privy to this conversation now are the CEO, the secretary, and anyone

right outside his office. (Shared variable)

3. The CEO, while IN his office with the door open AND the building wide INTERCOM

turned on, tells his secretary to do something.
The people privy to this conversation now are the CEO, the secretary,anyone right

outside his office, And everyone inside the entire warehouse building. (Global

variable)

The information that is told is the variable.
The CEO's office is a script/function.
The other people right outside the office are other open forms.
The entire warehouse is the entire application.
The scope is who can hear the information.

[KDR]

Re: Variable declaration?

Okay . . . so, if these other forms are already open (for instance, initialized but not activated when the primary form opens, and then activated as necessary when the button in question is pushed) then they could see the shared vars?

[MikeC]

Re: Variable declaration?

My understanding is if a variable is dimensioned shared from a form.....any other form that is open can see the variable---they don't have to be opened when the variable is dimmed, just open while the form that dimmed the variable is. Hey, try it and see....takes but a few seconds to test. If it cannot see it for some reason, try global and if it works, your work is done....

It has been stated that there is no real overhead with having ALL variables global....but there are other reasons not to such as then a variable will maintain its value when perhaps it is not wanted or accounted for, causing the same named variable being used elsewhere to have a value not wanted/intended.....making certain EVERY variable has a different name would eliminate this problem, but sometimes that is hard to accomplish.