WaitFor, TEvents and all that

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2 total messages Started by Ian Boag Tue, 07 Nov 2000 00:00

#317

Author: Ian Boag
Date: Tue, 07 Nov 2000 00:00

28 lines
1699 bytes

I am trying to get to grips with using WaitFor and TEvents. So I have put
together a very simple program that encapsulates my problem. It has two
buttons an a list box. Whan I click Button1, it sets off a process that
waits for Button2 to be clicked. The a message is put up  ...

First I make a TEvent (MyEvent) and Create it.

Form1.Create is
MyEvent.Create(nil,false,false,'');

Button1Click is then
  MyEvent.ResetEvent   (turns it "off")
  MyEvent.WaitFor(20000); (wait 20 seconds)
  write some sort of message

Button2Click is just
  MyEvent.Set

When I do all this I get an exception error to do with accesses and stuff
that I don't understand any of. Anyone able to help?

The reason I want to do this is actually much more complicated that two
buttons, but if I can make this one work I'll be able to do the auto FTP
client that I an REALLY trying to build ....

       Cheers

          Ian Boag

Re: WaitFor, TEvents and all that

#316

Author: Olaf Kaul
Date: Tue, 07 Nov 2000 00:00

37 lines
1382 bytes

On Tue, 7 Nov 2000 21:26:23 +1300, "Ian Boag"
<ianboag@partslink.co.nz> wrote:


>First I make a TEvent (MyEvent) and Create it.
>
>Form1.Create is
>MyEvent.Create(nil,false,false,'');
>
>Button1Click is then
>  MyEvent.ResetEvent   (turns it "off")
You did reset the event, before you started to wait for it.
For the Method "waitfor" the event will never be signaled.


>  MyEvent.WaitFor(20000); (wait 20 seconds)
>  write some sort of message
>
>Button2Click is just
>  MyEvent.Set
>


try this in Button 1 Click:

case MyEvent.WaitFor(20000) of
    wrSignaled:  
       Begin    
         MyEvent.ResetEvent;Edit1.text:='Signaled';
       End;
  
     wrTimeout:Edit1.Text:='timeout';
  end;



Olaf

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