How To Code MsgBox

[Peter.Greulich]

Re: How To Code MsgBox

You CAN use it in a script. e.g. in System Events, and the script naturally pauses at the confirm box. When the user clicks OK or Cancel you can direct the flow of the action accordingly. No problem. What you can't do (or at least I can't think of a way) is to use the confirm box as the "return" to an xbasic callback function. The function returns the confirmbox which returns "ok" (actually true or false). Now what? There is no way to direct the output. If you tag another callback function after the first, it's too late. Both functions run asynchronously. That's the client-server dilemna. Once this is clear to you, you will think differently about the problem.

[kingcarol]

Re: How To Code MsgBox

Peter, Thank You.

Result of this investigation.... I don't think I'd ever be able to convert my Custom Homebuilders' Solutions software to a web app. If you just watch the 2 videos on this page (http://www.chsbuildersoftware.com/Pa...es_Checks.html) about Post Job Costs, Parts 1 and 2, you'll see what I would be up against. Just notice how many times I check for things and pop up messages that then trigger other things. You have to watch for awhile to see the really active pop up stuff happening.

What I've been describing in this thread is just one tiny tip of a huge iceberg.

[Peter.Greulich]

Re: How To Code MsgBox

Yes, Carol. You have a very sophisticated application there. It's not the kind of program that I would want to convert to a web app as my first project w. Alpha. Could it be done? Sure. But you would need to change methodology in many places to accomplish the same thing as what you have now. Neither easy nor simple by any means - but rather, a major undertaking.

[kingcarol]

Re: How To Code MsgBox

Yep, if I do anything with Alpha, I'm now coming to the conclusion that it can only be a 'CHS Web Buddy' that lets builders do simple lookups of info they have in CHS, and maybe some small things like giving their home buyers and subcontractors a place to review builder authorized info from CHS.

[Peter.Greulich]

Re: How To Code MsgBox

...What you can't do (or at least I can't think of a way) is to use the confirm box as the "return" to an xbasic callback function.

Seriously, I'm going brain-dead. You CAN do this. The trick is to call a JS function with the confirm dialog, which in turn executes (or not) an xbasic callback function. Whew!

[kingcarol]

Re: How To Code MsgBox

Well, Peter, I was thinking that if Selwyn could do the coding he gave that has the alert box in it, and then have some coding after it, then what we were concluding about being thrown out of the code once the box was called was not making sense.

So, is that what he did? Call a JS function? in his code for the alert box (see below). And now we're back to (full circle), how do I do the same thing with the confirm box and use the result? Am I supposed to create JSconfirmBox somewhere first?

The first section below is me trying to use the confirm box. The 2nd section is me trying to figure out what to use as the result for an if statement. Within the if statement in the 2nd block of code below is code from Selwyn for the alert box and it DOES WORK.

dim confirmMsg as c
confirmMsg = "Press OK to confirm the delete."
confirmMsg = js_escape(confirmMsg)
'Do I need to dim the JSconfirmBox? As what?
JSconfirmBox = "confirm('" + confirmMsg + "');"

'If I can ever get the confirm box to pop up, can I grab its result?

If JSconfirmBox = "false" then
'user did not click ok to confirm the delete
cn.Close()
dim msg as c
msg = "The record has not been deleted per your request."
msg = js_escape(msg)
dim jscmd as c
jscmd = "alert('" + msg + "');"
LookupInChildTablesThenDeleteIfNotFound = jscmd
exit function
end if

[Selwyn Rabins]

How To Code MsgBox - an In-depth Example

Here is an in-depth example of how a server-side event can prompt the user for confirmation. See video number 85.

http://news.alphasoftware.com/v10preview/videos.htm

I hope that the videos make it clear that if server side code wants to prompt the user for any type of input, this has to be done in Javascript on the client-side. The server side code needs to CONSTRUCT the Javascript commands that prompt the user for input and then send these commands to the browser where they will execute.

The Javascript commands will then prompt the user for input, and then depending on the input, will initiate another callback to the server to continue processing.

It is clearly more complex than a desktop application where you don't have to think about client-side and server-side code execution. But once you 'get it' you will find that it not difficult to code.

With regard to Carol's comments that her Access app is too complex to convert to a Web application, I disagree strongly. The videos she has show us of her app show forms that have a lot of 'rules' on them that govern what the user can and cannot do, but there is nothing she has shown that does not have a web analogy.

[kingcarol]

Re: How To Code MsgBox

Hi Selwyn - I am SO excited to watch the videos and very impressed that you have pursued this. One problem, though, all seven of the links point to the very same video. I can only imagine how tired it made you to do this, so I completely get why that would happen at the end of your hard work. I look forward to viewing these tomorrow. Bed time now or I'd try changing the end of the url address in my browswer to Part2, Part3, etc. and probably find the other videos.

THANK YOU, THANK YOU, THANK YOU!

[Selwyn Rabins]

Re: How To Code MsgBox

Hi Selwyn - I am SO excited to watch the videos and very impressed that you have pursued this. One problem, though, all seven of the links point to the very same video. I can only imagine how tired it made you to do this, so I completely get why that would happen at the end of your hard work. I look forward to viewing these tomorrow. Bed time now or I'd try changing the end of the url address in my browswer to Part2, Part3, etc. and probably find the other videos.

THANK YOU, THANK YOU, THANK YOU!

ok, i fixed the links. sorry about that.

[kingcarol]

Re: How To Code MsgBox

Selwyn - Those videos are outstanding and I'm going to get started implementing that confirm box and doing the 2nd callback. If that's successful, I might also get carried away and try out the javascript Prompt box to have the user enter their name and see if I can capture it to append a record to my back end audit table that tracks deletions and who executed them. (of course, once we're live I probably won't need to do that since I'll probably be able to somehow get the user's id from their login. just want to play with the prompt box.... OH NO! :)

I'll play with just the confirm and doing 2nd callback until it's successful, though.

Can you email me the grid you used for the videos again? Or provide it here as a download for all viewing this thread? I'd like to copy some of your comments into my code for future reference.

And thank you for the info about right clicking on the Action Javascript for the button to see the script for executing the callback from the grid. I'd already been clicking the Type radial button to try to look at that, but the right click makes it so much handier.

I think this info alone opens up a whole new world for me in thinking about a future conversion of CHS into a web app.

[Selwyn Rabins]

Re: How To Code MsgBox

if you go back to the videos page, there is now a link after the link to the 7 videos to download the component.

[kingcarol]

Re: How To Code MsgBox

Selwyn - When that confirm box returns false(ie, user clicked to cancel the delete , do we need to close the connection that was opened? I noticed the cn.close is not in the Else part of the javascript. If we do need to close the connection, where do we put the cn.close... inside or outside of the confirm box javascript stuff?

[Selwyn Rabins]

Re: How To Code MsgBox

Selwyn - When that confirm box returns false(ie, user clicked to cancel the delete , do we need to close the connection that was opened? I noticed the cn.close is not in the Else part of the javascript. If we do need to close the connection, where do we put the cn.close... inside or outside of the confirm box javascript stuff?

actually, the first callback should close the connection before it sends the javascript response to the client.

so there is no need to close the connection if the user cancels because it is already closed.

if the user clicks OK in the confirm box, a new callback is initiated and that callback opens its own connection to the database.

in other words each callback is completely atomic - it is responsible for opening and closing its connections. you can't 'share' a connection between callbacks.

[kingcarol]

Re: How To Code MsgBox

OK, that makes sense about the callback closing the connection on its own before the javascript is sent to client. I had just noticed that you did do the cn.close before the code that used the javascript alert box earlier in the code before exiting the function and stopping. So I thought it might also be necessary with the return of false on the confirm box, since false from the confirm box will cause exit of the function without the second callback being made.

[Peter.Greulich]

Re: How To Code MsgBox - an In-depth Example

Here is an in-depth example of how a server-side event can prompt the user for confirmation. See video number 85.

http://news.alphasoftware.com/v10preview/videos.htm

FYI: At the time of this post, the above link is dead.

With regard to Carol's comments that her Access app is too complex to convert to a Web application, I disagree strongly.

I didn't say it couldn't be done. Just that I wouldn't want to attempt that as my first Alpha web app. Carol's application is VERY complex and quite sophisticated. From my point of view it represents a challenge, not an obstacle. Any project that daunting can be chipped away at one step at a time. Not to mention that Carol clearly is a very skilled programmer.