VB COM, Timer control disables Terminate event of ActiveX control

Timer control disables Terminate event of ActiveX control

Author	Message
Bhasker #1 / 6	Timer control disables Terminate event of ActiveX control Hi everybody, I've devloped a VERY simple ActiveX control in VB. The following is what I did : Create a VB project (ActiveX control) Insert a checkbox on the Usercontrol form Insert a timer control on the Usercontrol form Put the following code : Public x As CheckBox 'In the "General" section Private Sub UserControl_Initialize() Timer1.Enabled = True Set x = UserControl.Check1 End Sub Private Sub UserControl_Terminate() MsgBox "Terminate" End Sub When the above code is run, the 'Terminate' method is not called when the ActiveX control is destroyed. Howerver, commenting the line 'Timer1.Enabled = True' call the 'Terminate' method when the ActiveX control is destroyed. Any idea why this happens ?? Thanks for any help, Bhasker.
Sun, 05 Dec 2004 13:00:34 GMT

Bhasker #2 / 6	Timer control disables Terminate event of ActiveX control Hi all, Please let me know if you were able to simulate the issue. If you were not able to simulate the same, I could send you the VB project. Bhasker. Quote: >-----Original Message----- >Hi everybody, >I've devloped a VERY simple ActiveX control in VB. The following is what I >did : > Create a VB project (ActiveX control) > Insert a checkbox on the Usercontrol form > Insert a timer control on the Usercontrol form > Put the following code : >Public x As CheckBox 'In the "General" section >Private Sub UserControl_Initialize() > Timer1.Enabled = True > Set x = UserControl.Check1 >End Sub >Private Sub UserControl_Terminate() >MsgBox "Terminate" >End Sub >When the above code is run, the 'Terminate' method is not called when the >ActiveX control is destroyed. Howerver, commenting the line 'Timer1.Enabled Quote: >= True' call the 'Terminate' method when the ActiveX control is destroyed. - Hide quoted text - - Show quoted text - Quote: >Any idea why this happens ?? >Thanks for any help, >Bhasker. >.
Sat, 11 Dec 2004 14:01:04 GMT

Michael Col #3 / 6	Timer control disables Terminate event of ActiveX control Quote: > Hi everybody, > I've devloped a VERY simple ActiveX control in VB. The following is > what I did : > Create a VB project (ActiveX control) > Insert a checkbox on the Usercontrol form > Insert a timer control on the Usercontrol form > Put the following code : > Public x As CheckBox 'In the "General" section > Private Sub UserControl_Initialize() > Timer1.Enabled = True > Set x = UserControl.Check1 > End Sub > Private Sub UserControl_Terminate() > MsgBox "Terminate" > End Sub > When the above code is run, the 'Terminate' method is not called when > the ActiveX control is destroyed. Howerver, commenting the line > 'Timer1.Enabled = True' call the 'Terminate' method when the ActiveX > control is destroyed. > Any idea why this happens ?? Possibly because whilst the timer is still active, the control cannot be destroyed. Before trying to destroy the control, disable the timer. Note that simply dropping your reference to the control will not nessesarily destroy the control. If the timer remains active, you now have a memory leak.
Sun, 12 Dec 2004 10:32:19 GMT

Bhasker #4 / 6	Timer control disables Terminate event of ActiveX control Hi, Even if I say "Timer1.Enabled = False" immediately after the line "Timer1.Enabled = True", the 'Terminate' method is not called. However, if I say set x = nothing after the line Set x = UserControl.Check1 then the terminate method is called !! You had suggested that the timer be disabled before the control is destroyed, but how can I determine if the control is being destroyed - the only way is on 'Terminate' being called !! Thanks for the suggestion, Bhasker. Quote: > > Hi everybody, > > I've devloped a VERY simple ActiveX control in VB. The following is > > what I did : > > Create a VB project (ActiveX control) > > Insert a checkbox on the Usercontrol form > > Insert a timer control on the Usercontrol form > > Put the following code : > > Public x As CheckBox 'In the "General" section > > Private Sub UserControl_Initialize() > > Timer1.Enabled = True > > Set x = UserControl.Check1 > > End Sub > > Private Sub UserControl_Terminate() > > MsgBox "Terminate" > > End Sub > > When the above code is run, the 'Terminate' method is not called when > > the ActiveX control is destroyed. Howerver, commenting the line > > 'Timer1.Enabled = True' call the 'Terminate' method when the ActiveX > > control is destroyed. > > Any idea why this happens ?? > Possibly because whilst the timer is still active, the control cannot be > destroyed. Before trying to destroy the control, disable the timer. Note > that simply dropping your reference to the control will not nessesarily > destroy the control. If the timer remains active, you now have a memory > leak.
Sun, 12 Dec 2004 18:57:55 GMT

Michael Col #5 / 6	Timer control disables Terminate event of ActiveX control Quote: > Hi, > Even if I say "Timer1.Enabled = False" immediately after the line > "Timer1.Enabled = True", the 'Terminate' method is not called. > However, if I say > set x = nothing > after the line > Set x = UserControl.Check1 Why are you setting x to the checkbox? If you simply want to access the check box from outside, then use a Property Get. -- Regards, Michael Cole
Mon, 13 Dec 2004 09:21:30 GMT

Bhasker #6 / 6	Timer control disables Terminate event of ActiveX control Hi, The actual scenario is something like this : I have two grid controls on my ActiveX control form. At any given time, only one of them will be visible. When large amount of data is being fetched, the invisible grid is populated (to avoid flickering and other not-so-nice GUI operations on the grid) at the background (through a timer). When the data is fetched completely, the visible state of the two grids is swapped and x (equated to a checkbox in my code) will actually point to the currently active (visible) grid. This will help in having just one grid object (i.e., x) for both the grids, and therefore, my code becomes generic (with respect to accessing methods of the grids and its events). Bhasker. Quote: > > Hi, > > Even if I say "Timer1.Enabled = False" immediately after the line > > "Timer1.Enabled = True", the 'Terminate' method is not called. > > However, if I say > > set x = nothing > > after the line > > Set x = UserControl.Check1 > Why are you setting x to the checkbox? > If you simply want to access the check box from outside, then use a Property > Get. > -- > Regards, > Michael Cole
Tue, 14 Dec 2004 12:32:14 GMT

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