Why does this code run twice

[dbuchanan]

Hello,

I can find no reason for this code to run twice. Can you help me?

It may have something to do with it being a overrides sub but stepping
through during debug does *not* bear this out.


In the base class form...
\\
Protected Overridable Sub btnInsertCmptPr ofile_Click(ByV al sender As
System.Object, _
ByVal e As System.EventArg s) Handles btnInsertCmptPr ofile.Click

Throw New NotImplementedE xception

End Sub
//

In the derived form...
\\
Protected Overrides Sub btnInsertCmptPr ofile_Click(ByV al sender As
System.Object, _
ByVal e As System.EventArg s) Handles btnInsertCmptPr ofile.Click

'Get profiledata from master
Call InsertCmptProfi le()

'Creates two new row objects in code and saves them to the database
Call InsertValveForC ylinder()

'Retreive new and current data
Call ClearAndReloadF orm()

End Sub '<<(stepping through in debug mode) the code from here returns
to the top of this Sub and starts over. Why?
//

While stepping through the code I discovered that it just runs the
derived code block twice. Why? What is the correct why to make it run
once?

Thank you,
dbuchanan

[Jay B. Harlow [MVP - Outlook]]

Re: Why does this code run twice

dbuchanan,
| While stepping through the code I discovered that it just runs the
| derived code block twice. Why?
Because your base class is handling the event and also your derived class,

| What is the correct why to make it run
| once?
Rather then have btnInsertCmptPr ofile_Click as Overridable I would simply
have an overridable OnInsertCmptPro file that the event handler calls. This
hides (encapsulates) that an event is involved, which allows
OnInsertCmptPro file to possibly be called in other cases...

| In the base class form...
| \\
| Private Overridable Sub btnInsertCmptPr ofile_Click(ByV al sender As
| System.Object, _
| ByVal e As System.EventArg s) Handles btnInsertCmptPr ofile.Click
OnInsertCmptPro file()
End Sub

Protected Overridable Sub OnInsertCmptPro file ()
| Throw New NotImplementedE xception
| End Sub

| In the derived form...
| \\
| Protected Overrides Sub OnInsertCmptPro file()
...
| End Sub


Remember that one or more event handlers can each handle one or more events.

Private Sub AnEventHandler( sender As Object, e As EventArgs) _
Handles Button1.Click, Button2.Click
' this routine handles two buttons
End Sub

Private Sub AnotherEventHan dler(sender As Object, e As EventArgs) _
Handles Button1.Click
' this routine has some additional code for Button1.Click
End

Both AnEventHandler & AnotherEventHan dler will be called on Button1.Click,
while only AnEventHandler will be called for Button2.Click

--
Hope this helps
Jay
T.S. Bradley - http://www.tsbradley.net


"dbuchanan" <dbuchanan52@ho tmail.com> wrote in message
news:1128455175 .358485.271040@ g14g2000cwa.goo glegroups.com.. .
| Hello,
|
| I can find no reason for this code to run twice. Can you help me?
|
| It may have something to do with it being a overrides sub but stepping
| through during debug does *not* bear this out.
|
|
| In the base class form...
| \\
| Protected Overridable Sub btnInsertCmptPr ofile_Click(ByV al sender As
| System.Object, _
| ByVal e As System.EventArg s) Handles btnInsertCmptPr ofile.Click
|
| Throw New NotImplementedE xception
|
| End Sub
| //
|
| In the derived form...
| \\
| Protected Overrides Sub btnInsertCmptPr ofile_Click(ByV al sender As
| System.Object, _
| ByVal e As System.EventArg s) Handles btnInsertCmptPr ofile.Click
|
| 'Get profiledata from master
| Call InsertCmptProfi le()
|
| 'Creates two new row objects in code and saves them to the database
| Call InsertValveForC ylinder()
|
| 'Retreive new and current data
| Call ClearAndReloadF orm()
|
| End Sub '<<(stepping through in debug mode) the code from here returns
| to the top of this Sub and starts over. Why?
| //
|
| While stepping through the code I discovered that it just runs the
| derived code block twice. Why? What is the correct why to make it run
| once?
|
| Thank you,
| dbuchanan
|

[Jon Skeet [C# MVP]]

Re: Why does this code run twice

dbuchanan <dbuchanan52@ho tmail.com> wrote:[color=blue]
> I can find no reason for this code to run twice. Can you help me?
>
> It may have something to do with it being a overrides sub but stepping
> through during debug does *not* bear this out.[/color]

Have you subscribed to the event twice, perhaps?

--
Jon Skeet - <skeet@pobox.co m>
http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
If replying to the group, please do not mail me too

[Cor Ligthert [MVP]]

Re: Why does this code run twice

Hi,

In addition to Jay, you have added two handlers, so remove one of those.
Which depends in my opinion from the way that is for you normal to add an
handler.

I hope this helps,

Cor


"dbuchanan" <dbuchanan52@ho tmail.com> schreef in bericht
news:1128455175 .358485.271040@ g14g2000cwa.goo glegroups.com.. .[color=blue]
> Hello,
>
> I can find no reason for this code to run twice. Can you help me?
>
> It may have something to do with it being a overrides sub but stepping
> through during debug does *not* bear this out.
>
>
> In the base class form...
> \\
> Protected Overridable Sub btnInsertCmptPr ofile_Click(ByV al sender As
> System.Object, _
> ByVal e As System.EventArg s) Handles btnInsertCmptPr ofile.Click
>
> Throw New NotImplementedE xception
>
> End Sub
> //
>
> In the derived form...
> \\
> Protected Overrides Sub btnInsertCmptPr ofile_Click(ByV al sender As
> System.Object, _
> ByVal e As System.EventArg s) Handles btnInsertCmptPr ofile.Click
>
> 'Get profiledata from master
> Call InsertCmptProfi le()
>
> 'Creates two new row objects in code and saves them to the database
> Call InsertValveForC ylinder()
>
> 'Retreive new and current data
> Call ClearAndReloadF orm()
>
> End Sub '<<(stepping through in debug mode) the code from here returns
> to the top of this Sub and starts over. Why?
> //
>
> While stepping through the code I discovered that it just runs the
> derived code block twice. Why? What is the correct why to make it run
> once?
>
> Thank you,
> dbuchanan
>[/color]

[TrtnJohn]

RE: Why does this code run twice

Everyone is right. The event will call all registered delagates is why you
get the call twice. Typically it is better in the base class to implement
eventhandlers like this:

Private Sub btnInsertCmptPr ofile_Click(ByV al sender As System.Object, _
ByVal e As System.EventArg s) Handles btnInsertCmptPr ofile.Click

OnProfileClick( sender,e)
End Sub

Protected Overridable Sub OnProfileClick( ByVal sender As System.Object, _
ByVal e As System.EventArg s)
Throw New NotImplementedE xception
End Sub

Or, in your case it may even be better to declare OnProfileClick as
MustOverride.


"dbuchanan" wrote:
[color=blue]
> Hello,
>
> I can find no reason for this code to run twice. Can you help me?
>
> It may have something to do with it being a overrides sub but stepping
> through during debug does *not* bear this out.
>
>
> In the base class form...
> \\
> Protected Overridable Sub btnInsertCmptPr ofile_Click(ByV al sender As
> System.Object, _
> ByVal e As System.EventArg s) Handles btnInsertCmptPr ofile.Click
>
> Throw New NotImplementedE xception
>
> End Sub
> //
>
> In the derived form...
> \\
> Protected Overrides Sub btnInsertCmptPr ofile_Click(ByV al sender As
> System.Object, _
> ByVal e As System.EventArg s) Handles btnInsertCmptPr ofile.Click
>
> 'Get profiledata from master
> Call InsertCmptProfi le()
>
> 'Creates two new row objects in code and saves them to the database
> Call InsertValveForC ylinder()
>
> 'Retreive new and current data
> Call ClearAndReloadF orm()
>
> End Sub '<<(stepping through in debug mode) the code from here returns
> to the top of this Sub and starts over. Why?
> //
>
> While stepping through the code I discovered that it just runs the
> derived code block twice. Why? What is the correct why to make it run
> once?
>
> Thank you,
> dbuchanan
>
>[/color]

[Roger Rabbit]

Re: Why does this code run twice

If using VS.Net remember you can always use the call stack debugging window
to review the caller code.

RR


"dbuchanan" <dbuchanan52@ho tmail.com> wrote in message
news:1128455175 .358485.271040@ g14g2000cwa.goo glegroups.com.. .[color=blue]
> Hello,
>
> I can find no reason for this code to run twice. Can you help me?
>
> It may have something to do with it being a overrides sub but stepping
> through during debug does *not* bear this out.
>
>
> In the base class form...
> \\
> Protected Overridable Sub btnInsertCmptPr ofile_Click(ByV al sender As
> System.Object, _
> ByVal e As System.EventArg s) Handles btnInsertCmptPr ofile.Click
>
> Throw New NotImplementedE xception
>
> End Sub
> //
>
> In the derived form...
> \\
> Protected Overrides Sub btnInsertCmptPr ofile_Click(ByV al sender As
> System.Object, _
> ByVal e As System.EventArg s) Handles btnInsertCmptPr ofile.Click
>
> 'Get profiledata from master
> Call InsertCmptProfi le()
>
> 'Creates two new row objects in code and saves them to the database
> Call InsertValveForC ylinder()
>
> 'Retreive new and current data
> Call ClearAndReloadF orm()
>
> End Sub '<<(stepping through in debug mode) the code from here returns
> to the top of this Sub and starts over. Why?
> //
>
> While stepping through the code I discovered that it just runs the
> derived code block twice. Why? What is the correct why to make it run
> once?
>
> Thank you,
> dbuchanan
>[/color]