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run my form once
- Thread starter tseegii
- Start date
craigsboyd
IS-IT--Management
tseegii,
Did you mean have only a single instance of your application running at a time? If so, have a look at the following thread:
thread184-672388
Did you mean have only a single instance of your application running at a time? If so, have a look at the following thread:
thread184-672388
ChrisRChamberlain
Programmer
tseegii
The following snippit from a main.prg attempts to open the table errorlog.dbf, which as its name implies, logs any errors found and so the code needs to be placed right at the top of your main.prg.
It checks for the existence of the table and by attempting to open it exclusively will then quit the application if the table is already in use by another instance of the application.
If your version of VFP does not support TRY...ENDTRY, you can use ON ERROR llError = .T., etc and construct a similar code block.
![[pc2]](/data/assets/smilies/pc2.gif "[pc2] [pc2]")
PDFcommander[sup]tm[/sup].net
PDFcommander[sup]tm[/sup].co.uk
The following snippit from a main.prg attempts to open the table errorlog.dbf, which as its name implies, logs any errors found and so the code needs to be placed right at the top of your main.prg.
It checks for the existence of the table and by attempting to open it exclusively will then quit the application if the table is already in use by another instance of the application.
If your version of VFP does not support TRY...ENDTRY, you can use ON ERROR llError = .T., etc and construct a similar code block.
Code:
[COLOR=blue]IF ADIR(laTemp,SYS(5) ;
+ ADDBS(SYS(2003)) ;
+ [tables\errorlog.dbf]) = 1
TRY
USE tables\errorlog IN 0 EXCLUSIVE
CATCH
MESSAGEBOX( ;
[Application appears to be either in use or] ;
+ CHR(13) ;
+ [maybe still shutting down from the last session.] ;
+ CHR(13) ;
+ CHR(13) ;
+ [Please try again in a few moments] ,;
16 ,;
[Application in use] ,;
3000)
QUIT
ENDTRY
ELSE
MESSAGEBOX( ;
[The ErrorLog table is missing from your application] ;
+ CHR(13) ;
+ CHR(13) ;
+ [Please reinstall the application] ,;
16 ,;
[ErrorLog table missing] ,;
3000)
QUIT
ENDIF[/color]FAQ184-2483 - answering getting answered.
Chris PDFcommander[sup]tm[/sup].net
PDFcommander[sup]tm[/sup].co.uk
Mike Lewis
Programmer
Tseegii,
I'm assuming you have a menu command or a button which launches the form. If the form is already running, you don't want to run it again.
The following function will do that. If the form is already running, it just brings it to the front. The function takes the form name as a parameter. Note that this depends on the form's SCX filename being the same as its Name property.
Mike
__________________________________
Mike Lewis (Edinburgh, Scotland)
My sites:
Visual FoxPro (www.ml-consult.demon.co.uk)
Crystal Reports (www.ml-crystal.com)
I'm assuming you have a menu command or a button which launches the form. If the form is already running, you don't want to run it again.
The following function will do that. If the form is already running, it just brings it to the front. The function takes the form name as a parameter. Note that this depends on the form's SCX filename being the same as its Name property.
Code:
LPARAMETERS tcFormName
LOCAL loForm, llOpen
tcFormName = UPPER(tcFormName)
llOpen = .F.
FOR EACH loForm IN _SCREEN.Forms
IF UPPER(loForm.Name) == tcFormName
* This is the one we want
loForm.Show
llOpen = .T.
EXIT
ENDIF
ENDFOR
IF NOT llOpen
* Not yet open, so open it now
DO FORM (tcFormName)
ENDIFMike
__________________________________
Mike Lewis (Edinburgh, Scotland)
My sites:
Visual FoxPro (www.ml-consult.demon.co.uk)
Crystal Reports (www.ml-crystal.com)
tseegii, are you there? If you really want to keep your application from running multiple times, these faq's should help:
faq184-2442 -- Using Windows "Atoms"
faq184-839 -- Using DDE (my favorite, since it allows other inter-program communication)
faq184-1998 -- Using Main Window Caption
faq184-1767 -- In Pre-Vfp6 (I think), using Main Window Caption, or Atoms
- Bill
Get the best answers to your questions -- See FAQ481-4875.
faq184-2442 -- Using Windows "Atoms"
faq184-839 -- Using DDE (my favorite, since it allows other inter-program communication)
faq184-1998 -- Using Main Window Caption
faq184-1767 -- In Pre-Vfp6 (I think), using Main Window Caption, or Atoms
- Bill
Get the best answers to your questions -- See FAQ481-4875.
If, on the other hand, you really wanted to know how to run your Form (within your application) just once.... that is very simple, and entirely dependant on how you are instantiating your forms.
For example, if you simply always assign your form to a global variable (so it can be referenced from everywhere in your program), then there will always be only one instance:
RELEASE goMyForm
PUBLIC goMyForm
DO myform NAME goMyForm LINKED
Of course, if you don't want instance #2 to release/replace instance #1, but simply to not open again:
if vartype(goMyForm)<>'O'
RELEASE goMyForm
PUBLIC goMyForm
DO myform NAME goMyForm LINKED
endif
This is the simplest (and not necessarily the best). Any more sophisticated way is very dependant on the design of your app: How do you launch your form(s)?
- Bill
Get the best answers to your questions -- See FAQ481-4875.
For example, if you simply always assign your form to a global variable (so it can be referenced from everywhere in your program), then there will always be only one instance:
RELEASE goMyForm
PUBLIC goMyForm
DO myform NAME goMyForm LINKED
Of course, if you don't want instance #2 to release/replace instance #1, but simply to not open again:
if vartype(goMyForm)<>'O'
RELEASE goMyForm
PUBLIC goMyForm
DO myform NAME goMyForm LINKED
endif
This is the simplest (and not necessarily the best). Any more sophisticated way is very dependant on the design of your app: How do you launch your form(s)?
- Bill
Get the best answers to your questions -- See FAQ481-4875.
- Thread starter
- #8
Mike Lewis
Programmer
Mike,
Make it modal.
Strongly disagree. There are many situations where you want to disallow multiple instances without having to do without the benefits of modeless forms.
Mike
__________________________________
Mike Lewis (Edinburgh, Scotland)
My sites:
Visual FoxPro (www.ml-consult.demon.co.uk)
Crystal Reports (www.ml-crystal.com)
Mike Lewis
Programmer
Mike,
OK, I guess we don't really disagree that much after all.
Mike
__________________________________
Mike Lewis (Edinburgh, Scotland)
My sites:
Visual FoxPro (www.ml-consult.demon.co.uk)
Crystal Reports (www.ml-crystal.com)
craigsboyd
IS-IT--Management
Mike Lewis
Programmer
I vehemently disagree, but not strongly
Actually, that's what I was trying to say <g>.
Mike
__________________________________
Mike Lewis (Edinburgh, Scotland)
My sites:
Visual FoxPro (www.ml-consult.demon.co.uk)
Crystal Reports (www.ml-crystal.com)
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