Cannot remove handler of an event with RemoveHandler

[marcoslob]

Hello everyone!

This is Marcos from Spain. This is my first post to tell you this little problem annoying me.

I am doing a very simple game, and it has a 10 seconds countdown. There is a big button for clicking and each time you click you get one point. The timer starts, and the countdown starts like this: (the following is a part of the Timer1.Tick event handler)

If Label4.Text > 0 Then
            Label4.Text = Label4.Text - 1
End If

assuming

Timer1.Interval = 1000

So, when the countdown reaches zero, what I'd like to do is to STOP handling the Button2.Click event and what I wrote was this:

If Label4.Text = 0 Then
            RemoveHandler Button2.Click, Button2_Click()
            Timer1.Stop()
        End If

Basicly, it ain't working. When I click on the button it keeps adding points.

Keep in mind that after playing one time, the user must be able to play more times. The program was fully working with a Start/Stop button, but 1. I need challenge and learning and 2.The user loses time clicking the button. So please stick to this solution, because I've thought on a MouseHover starting system.

Thank you so much from a noob.

[formlesstree4]

You're probably going about this the wrong way. Why not just disable the button? Also, subtracting like that is a very bad idea and can cause all sorts of problems.

[Evil_Giraffe]

I would assume RemoveHandler only removes handlers added with AddHandler. I'm guessing you've got a 'Handles Button2.Click' to wire it up, yes?

[marcoslob]

You're probably going about this the wrong way. Why not just disable the button? Also, subtracting like that is a very bad idea and can cause all sorts of problems.

The problem with disabling the button is that I the MouseHover event wouldn't work. I tried and I didn't, but if you can tell me how with the Button disabling method I'd be really happy!

[marcoslob]

I would assume RemoveHandler only removes handlers added with AddHandler. I'm guessing you've got a 'Handles Button2.Click' to wire it up, yes?

Sure, I have a Handles Button2.Click on the Sub.

[marcoslob]

Aaand... I'd love to know how to substract on a better way. Or a different way for the countdown.

[dunfiddlin]

Am I missing something? Wouldn't a simple ...

If Label4.Text <> "0"

... or similar at the head of all the code in the Click event effectively enable/disable it?

[marcoslob]

Am I missing something? Wouldn't a simple ...

If Label4.Text <> "0"

... or similar at the head of all the code in the Click event effectively enable/disable it?

Ehr... I think so. And I'm stupid. Let me have a try, maybe I am missing something.

[marcoslob]

Am I missing something? Wouldn't a simple ...

If Label4.Text <> "0"

... or similar at the head of all the code in the Click event effectively enable/disable it?

Did work indeed. Would love to hear from formlesstree4 about the proper way for countdowns.

[Evil_Giraffe]

There are two issues with the subtraction. The first is that you're doing arithmetic on strings. You should be keeping the numeric value of the countdown in a numeric field, something like this:

Private _countdown As Integer ' Initialise this to 10 just before you start the timer
 
Private Sub Timer1_Tick(sender As System.Object, e As System.EventArgs) Handles Timer1.Tick
    If _countdown > 0 Then
        _countdown = _countdown - 1
        Label4.Text = _countdown.ToString()
    End If
End Sub

The second issue is that you're not guaranteed to get the timer to tick at exactly 1 second intervals. We're talking microseconds difference, but still, worth bearing in mind. There are ways around this if it is very important but they up the complexity of the code by quite a degree so really decide whether it's worth getting in to the quagmire (especially given that you can't actually guarantee exactly 10s whatever way you do it)

[techgnome]

The removeHandler is syntatically wrong.... if one was to check the documentation, one would find that the two parameters is 1) the Event, and 2) the DELEGATE to the event handler... NOT the name of the event handler. Eh? What's that mean? Means you need to pass it the ADDRESS of the handler...

RemoveHandler Button2.Click, AddressOf Button2_Click

-tg