Working with Parameters

[admdev]

Hi all,

Hope you can help!

I am sending a parameter from Form A to Form B as such.

NEWOBJECT('frmtest', 'testclass.vcx','',parameter)

While in Form B, I am updating the value and I would like to send it back to Form A.

Could anybody help with this?

Thanks in advance.

 

[ilyad]

Use parameter object instead of the static parameter. This way you can change its properties in any form and they would be accessible.

e.g.

loParm = createobject('custom')
loParm.AddProperty('myProp','')

formA calls formB with this loParm, formB can modify its properties and the changes would be now accessible in formA.

 

[admdev]

Will this object be part of FormA?

Thanks.

 

[ilyad]

It doesn't have to be.

 

[Mike Lewis]

One way to do this would be to pass the parameter by reference . To achieve that, put an ampersand in front of it (in the calling code):

NEWOBJECT('frmtest', 'testclass.vcx','',&parameter)

Then, in Form B, just update the value in the usual way. However, you must do that in the Init of Form B.

Also, none of these methods will work unless Form B is modal.

Mike


__________________________________
Mike Lewis (Edinburgh, Scotland)

My Visual FoxPro site: www.ml-consult.co.uk

 

[opticalman]

I frequently send parameters to forms and recieve a returned value from the called form when it closes. The called form assigns a vaule to ThisForm.Tag. In the UNLOAD event of the called form ( your form B ) I place:
RETURN ThisForm.Tag
Here is a CODE SAMPLE from one of my functions where a value is returned to local variable cChoice.

DO FORM FORMS\YesNo WITH cText,lDefault , nLeft , nTop  TO cChoice

IF	cChoice = 'YES'
      lReturn = .T.
ELSE
	lReturn = .F.
ENDIF
RETURN lReturn

I hope this helps

Jim Rumbaugh

 

[Imaginecorp]

I frequently send parameters to forms and recieve a returned value from the called form when it closes.

Another way would be with Modal as well as Modeless forms and you dont have to wait till it closes:

In the called (child) form's INIT()
lParameters pWhoCalled
with this
.addproperty("WhoCalled",pWhoCalled)
.....
.....
endwith

Now in the calling (parent) form:
do form <<childform>> with thisform

Now from the child form you can access any event, method & property with
Thisform.whocalled.<< any thing>>

There are a lot of variations to this. If the form is not Modal and you want to access the child form while its open from the parent:
Create a property in the parent form called "child form" or whatever before you call the child form.
In the INIT() of the child form:
Thisform.whocalled.childform = this

Now you can have a 2 way Conversation

Again: this is to give you an idea, you will have to fine tune

 

[admdev]

Thanks guys for all your suggestions.

I will try the suggested solutions and get back here to post what best worked for me.

Thanks.

 

[admdev]

Thanks for your help guys!

What I am doing is what ilyad suggested. I am passing the form A as a parameter to Form B. Within form B I am able to modify any properties on form A.

Thanks.

 

[ilyad]

You're welcome Didn't you forget to mark helpful responses?

 

[Mike Lewis]

Ilyad,

Didn't you forget to mark helpful responses?

Could I respectfully point out that that remark is contrary to Tek Tips policies and etiquette. Whether a member chooses to mark a post as helpful is entirely a matter for them to decide. The management frowns on messages that solicit such a response.

I hope you don't mind me pointing this out. I've noticed you've posted a similar remark in other threads. You are an active member of this forum, and forum members rightly value your contributions. I wouldn't want anyone on the management side to give you a bad time over this.

Mike


__________________________________
Mike Lewis (Edinburgh, Scotland)

My Visual FoxPro site: www.ml-consult.co.uk

 

[NasibKalsi]

I like opticalman's solution, where there is no need for helpers to carry the gift from UNLOAD event. As UNLOAD is the official gift distributor.

 

[ilyad]

Sorry, Mike. I will not do that again.

 

[Olaf Doschke]

Mike,

jsu one thing, you meant @, not ampersand, for sending a parameter by reference.

This could work too, but has it's disadvantage, if passing the parameter to a form, because that parameter get's out of scope, after form Bs init has run.

passing formA as reference to formB is a good solution, if formB runs modal. If not, you could get problems releasing formA, especially if you store that reference to formA in a property of formB. Then a seperate Parameter object has some advantages. Since VFP8 you can make use of the lightweight object class "empty".

Bye, Olaf.