Proper way to change variables in a form?

[jjfcpa]

I've read a number of posts on this board regarding variable scoping and I'm really just looking for some verification on the most efficient way to do this. I find myself needing to do this all the time, and quite honestly, still not sure exactly what is the preferred method.

Here is a description of what I need to do.

1. Call a function.
2. Create some variables.
3. Call a form to let the user change the variables.
4. Return to the function and proceed based on the content of the variables.

I should add that the variables relate to data stored in a table; however, I don't want to use a typical data entry screen to allow them to change these values. I will update the table in the function after the form closes.

My question relates to how I should "scope" the variables so that the form has access to them and what do I need to do so the form has access to them. It is my understanding that the function can see the variables, but the form (since it's a new session) will not be able to see them.

A short code snippet that could serve as a template for reference would be extremely helpful.

[Stan Mathews]

Re: Proper way to change variables in a form?

If you will permit a bit of paraphrasing and rearranging I would


1. Open a form with the variables defined for the form as session variables.
2. Allow the user to change the default values to suit
3. Call a function passing the variables as parameters

[jjfcpa]

Re: Proper way to change variables in a form?

If you will permit a bit of paraphrasing and rearranging I would


1. Open a form with the variables defined for the form as session variables.
2. Allow the user to change the default values to suit
3. Call a function passing the variables as parameters

Stan

Assuming that the function needs to do some procedures first, I can't call the form before the function. I have to call the form from the function. In fact, the form may not even be called in some cases.

[forskare]

Re: Proper way to change variables in a form?

Stan

Assuming that the function needs to do some procedures first, I can't call the form before the function. I have to call the form from the function. In fact, the form may not even be called in some cases.

Hello John,

As you have noticed, it's all in the context. There is usually more than one way to achieve the end result and w/o know what it is you want to achieve, your answers will probably not be suited to your needs, as you just found out. Perhaps you could illustrate what you want to achieve and the pros like Stan could elaborate on the best way to accomplish it.

kenn

[MikeC]

Re: Proper way to change variables in a form?

:) Trial and error would be another way . Dim them as shared in your function and see if the form can use them....if not, then use global. Could start dimming as local, but am farily certain that would not be enough for most contexts.

OR for us (them) to give a more specific answer ...what kenn said.

[csda1]

Re: Proper way to change variables in a form?

Hi John,

Assuming that the function needs to do some procedures first, I can't call the form before the function. I have to call the form from the function. In fact, the form may not even be called in some cases.

I am reading between the lines, but I think what you are calling a form is merely user interface to get some variable values for the function to use. If that is the case, you want to place an XDialog box at the appropriate place in the function. Using a form as a modal dialog box is a very old way to do it, and I don't recommend it except for some very unusual cases.

If, on the other hand, the function processes variables created on a form, then you can initialize it on the form Init event, and call the function as needed. I typically use the same function for initialization and for processing, to keep the code together, and differentiate the usage by a shared or global flag indicating initialization, or via a parameter I pass to the function.

[jjfcpa]

Re: Proper way to change variables in a form?

Hi John,



I am reading between the lines, but I think what you are calling a form is merely user interface to get some variable values for the function to use. If that is the case, you want to place an XDialog box at the appropriate place in the function. Using a form as a modal dialog box is a very old way to do it, and I don't recommend it except for some very unusual cases.

If, on the other hand, the function processes variables created on a form, then you can initialize it on the form Init event, and call the function as needed. I typically use the same function for initialization and for processing, to keep the code together, and differentiate the usage by a shared or global flag indicating initialization, or via a parameter I pass to the function.

Ira

Thanks for your reply. While you are correct that this is just a modal form to get some information from the user, I really don't care for the xdialog (box, form, dialog). You don't have near the control you have with a form or you have to do it all in code, which is very different than xbasic code.

I'm coming from the Visual Foxpro world and in VFP, you can ask a question in a messagebox in the init of a form and if you "return .F." the form will never load. It was a really convenient way to use a form to ask a question that would determine if the form would load or not. It appears that this has to be done in a function in A5.

So I'm calling a function, which needs to ask a question. If answered one way, the form needs to load, if not, then the application quits. If the form is called, based on the answers to some questions on the form (variables), I need to act on the content of the variables.

So in summary,

Function is called, which asks a question.

If necessary,

initiate some variables
Call the form
Allow the user to change variables on the form

return to function to continue processing based on the contents of the variables.