Event is fired multiple times

**Matt F** · Jan 11 '07, 06:15 PM

Re: Event is fired multiple times

Random guess since I don't work with treeviews much:

Child object changes - fires event
Top Level object recognizes change of one of it's children, hence a change
to something in it's heiarchy, - fires event.

test: comment out "OnEvent TopLevelData.Pr opertyChanged, RaiseEvent
ObjectChanged" and modify child object - if only fires once, it give a
pretty good idea

"AMDRIT" <amdrit@hotmail .comwrote in message
news:uEN012ZNHH A.4604@TK2MSFTN GP06.phx.gbl...

Hello Everyone,
>
I am having an issue where an event appears to be fired repeatedly where I
only expect it to be fired once. See below for objects and behaviors.
>
I have a control that contains a treeview, it creates the TopLevel object
and subscribes to the ObjectChanged Event. When the event is fired, I
rebuild the treeview. If I change data from TopLevelData, the event is
fired just once. When I change data in ChildObject, the event is fired
multiple times. Perhaps the Event doesn't know it was heard and feels the
need to repeat itself.
>
I am sure I am missing something, anyone have any ideas what that is?
>
VB2005, WinXP
>
Here is a sample of what I am doing.
>
Class TopLevel
>
Readonly Property TopLevelData
Readonly Property ChildCollection
>
OnEvent ChildCollection .ListChanged, RaiseEvent ObjectChanged
OnEvent TopLevelData.Pr opertyChanged, RaiseEvent ObjectChanged
>
Class TopLevelData
>
On Property Change, RaiseEvent PropertyChanged
>
Class ChildCollection (ListOf ChildObject)
>
On Event ChildObject Property Change, RaiseEvent ListChanged
On Addition or Deletion of ChildObject, RaiseEvent ListChanged
>
Class ChildObject
>
On Property Change, RaiseEvent PropertyChanged
>
>
>

**AMDRIT** · Jan 11 '07, 06:35 PM

Re: Event is fired multiple times

Thanks for the reply.

I thought of these too, and am still perplexed.

Here is my logic for property set

Dim strTemp As String = pstrInstanceNam e

If String.Compare( value, strTemp, False) <0 Then
pstrInstanceNam e = value
Trace.WriteLine (String.Format( "Property:{ 0} changed",
"InstanceName") )
RaiseEvent PropertyChanged (Me, New
PropertyChanged EventArgs("Inst anceName", strTemp, pstrInstanceNam e))
End If

Below is trace log output. I have three actions: Create the TopLevel,
Create a ChildObject, Change a ChildObject property value.

Creating and instantiating the TopLevel Class
----------------------------------------------
Property:Projec tName changed
S T A R T B I N D I N G T R E E
E N D B I N D I N G T R E E

Creating a new BusinessObject object
-------------------------------------
Property:Busine ssObjects changed
List:ProjectInf os changed
S T A R T B I N D I N G T R E E
E N D B I N D I N G T R E E
Property:Busine ssObjects changed
List:ProjectInf os changed
S T A R T B I N D I N G T R E E
E N D B I N D I N G T R E E
Property:Busine ssObjects changed
List:ProjectInf os changed
S T A R T B I N D I N G T R E E
E N D B I N D I N G T R E E

Changing a property value in BusinessObject
-------------------------------------------
Property:Instan ceName changed
Property:Busine ssObjects changed
List:ProjectInf os changed
S T A R T B I N D I N G T R E E
E N D B I N D I N G T R E E
Property:Busine ssObjects changed
List:ProjectInf os changed
S T A R T B I N D I N G T R E E
E N D B I N D I N G T R E E
Property:Busine ssObjects changed
List:ProjectInf os changed
S T A R T B I N D I N G T R E E
E N D B I N D I N G T R E E
Property:Busine ssObjects changed
List:ProjectInf os changed
S T A R T B I N D I N G T R E E
E N D B I N D I N G T R E E
Property:Busine ssObjects changed
List:ProjectInf os changed
S T A R T B I N D I N G T R E E
E N D B I N D I N G T R E E
Property:Busine ssObjects changed
List:ProjectInf os changed
S T A R T B I N D I N G T R E E
E N D B I N D I N G T R E E
Property:Busine ssObjects changed
List:ProjectInf os changed
S T A R T B I N D I N G T R E E
E N D B I N D I N G T R E E

"Matt F" <mfielderREMOVE CAPS@nospam.nos pamwrote in message
news:%23KySqtaN HHA.4244@TK2MSF TNGP04.phx.gbl. ..

Random guess since I don't work with treeviews much:
>
Child object changes - fires event
Top Level object recognizes change of one of it's children, hence a change
to something in it's heiarchy, - fires event.
>
test: comment out "OnEvent TopLevelData.Pr opertyChanged, RaiseEvent
ObjectChanged" and modify child object - if only fires once, it give a
pretty good idea
>
>
>
>
"AMDRIT" <amdrit@hotmail .comwrote in message
news:uEN012ZNHH A.4604@TK2MSFTN GP06.phx.gbl...

>Hello Everyone,
>>
>I am having an issue where an event appears to be fired repeatedly where
>I only expect it to be fired once. See below for objects and behaviors.
>>
>I have a control that contains a treeview, it creates the TopLevel object
>and subscribes to the ObjectChanged Event. When the event is fired, I
>rebuild the treeview. If I change data from TopLevelData, the event is
>fired just once. When I change data in ChildObject, the event is fired
>multiple times. Perhaps the Event doesn't know it was heard and feels
>the need to repeat itself.
>>
>I am sure I am missing something, anyone have any ideas what that is?
>>
>VB2005, WinXP
>>
>Here is a sample of what I am doing.
>>
>Class TopLevel
>>
> Readonly Property TopLevelData
> Readonly Property ChildCollection
>>
> OnEvent ChildCollection .ListChanged, RaiseEvent ObjectChanged
> OnEvent TopLevelData.Pr opertyChanged, RaiseEvent ObjectChanged
>>
>Class TopLevelData
>>
> On Property Change, RaiseEvent PropertyChanged
>>
>Class ChildCollection (ListOf ChildObject)
>>
> On Event ChildObject Property Change, RaiseEvent ListChanged
> On Addition or Deletion of ChildObject, RaiseEvent ListChanged
>>
>Class ChildObject
>>
> On Property Change, RaiseEvent PropertyChanged
>>
>>
>>

>
>

Event is fired multiple times

Event is fired multiple times

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