I'm using vb.net 2013, and I have configured Shutdown mode to "When last form is closed".
On my main form, I have a menu item which has this code to close the application:
Application.Exit
Everything is working fine, except one case:
When I open a specific form, where a Combobox is created on runtime and I've used Addhandler to subscribe to several events.
The combobox is created when pressing a button.
When I open this form and I don't create the combobox, everything is working ok. If the combobox is created, when I close this form and try to close the application using the menu item, nothing happens. The application is not closed and no error message is displayed. (the same situation occurs when I try to close the main form with "x" button)
On the form's (where I have the combobox) close event , I tried to put a line of code:
MyCombobox.dispose()
But the situation is the same.
What can I do? Thank you!
What I do from my little experience is
1.) remove the MyCombobox from its parent control (I'm think this is in your combobox close event).
2.) set the MyCombobox to Nothing
3.) Dispose() it.
MyCombobox = Nothing
MyCombobox.Dispose()
It would be useful to see some part of your code for the close event so we can help you check. More power to you!
Update based on OP's comment:
I have read the following from MSDN: https://msdn.microsoft.com/en-us/library/system.windows.forms.form.closing(v=vs.110).aspx
From this, it is important to note that:
The Form.Closed and Form.Closing events are not raised when the Application.Exit method is called to exit your application. If you have validation code in either of these events that must be executed, you should call the Form.Close method for each open form individually before calling the Exit method.
Related
I have a form that opens a modal pop up helper form to collect some data. When this modal pop up form closes, focus returns to the main form. I would like to trigger some activity when focus comes back to my main form.
The event model for the form does not trigger the Form_Activate or Form_GotFocus events when returning from a model popup as per Microsoft documentation.
These forms and all controls are completely unbound.
Is there a trick to knowing in code when focus returns to my form?
If both forms are placed in normal mode, Form_Activate does fire in the primary form when the helper form closes, but this does not meet my needs. I have not been able to find a similar event to trap this. I'm hoping someone has a workaround.
For clarity, the issue I ran into was I had the design time properties in the helper form set to act as a dialog - (pop up and modal as true). When I opened the form responding to the button click event on the main form, I did NOT include the acDialog option.
If you omit the WindowMode=acDialog setting the code operates asynchronously completing the code in the click event handler in full, NOT halting and waiting.
The acDialog option apparently forces the DoCmd.OpenForm command to run synchronously, halting code execution, then returning once the modal form has been closed.
Private Sub btnHelper_Click()
DoCmd.OpenForm "frmHelper", WindowMode:=acDialog
'Do stuff after frmHelper closes
End Sub
What is the difference between form.Close() and form.Hide() in desktop application.
i know Form_Close event will not be fired in form.Hide() method what about other differences.
Is anyone faster?
form.Close() unloads the form from memory and makes it available to be garbage collected; you can no longer interact with the form in code.
form.Hide() just hides the form, but you can still interact with it in your code.
So it is not really a question of which one is faster, but rather "are you really done using this form or not"?
Hide makes the form invisible to the user. Close actually closes it and calls dispose on it.
From: http://msdn.microsoft.com/en-us/library/system.windows.forms.form.close(v=vs.110).aspx
"When a form is closed, all resources created within the object are closed and the form is disposed. "
Hide only hides the form from the screen. Close is of course closes the form. If you want to get rid of the form that you don't want to use anymore then you should use Close. Hide and Close are different things.
Ditto the above... Typically the way you open the form determines which to use. If you use .Show() the calling code continues while the form is loaded and shown. If you use ShowDialog() then calling code stops while the form is loaded and shown. When you Hide the called form the calling code resumes to the next statement.
Here is a sample of the second case:
Dim frm As New frmSearch2
frm.inFormName = "frmFacility"
frm.ShowDialog(Me)
If frm.outPrimaryKey.Length > 0 Then
frmMain.Open_Form("frmFacility", frm.outPrimaryKey)
End If
frm.Close
frm = Nothing
outPrimaryKey is a form level Public variable. You can also address any of the controls on the form.
In the program I'm writing, there is just one form. I've made a user control visible and it contains several buttons. One of the buttons is supposed to close the form when clicked. I can't find any way to do this without getting the error: "Cannot access a disposed object. Object name: 'ShapeContainer.'" I'm pretty sure I understand the problem; after the form has been closed, the user control no longer exists, so there's an error when Form.Close() (I've tried Form.Dispose() too) has completed and it tries to go back to the code inside the button click event. Does anyone know how I could accomplish closing the form through this user control's button without getting the error?
Okay I'm pretty new to vb but I think if you get rid of the Form.Dispose() & Form.Close then try Me.Close() as you are referring to the current Form that the button control is located on.
You Should have got this error:
(Error 1 'NameSpace_.Form1' cannot refer to itself through its default instance; use 'Me' instead.)
I have a form in a Pocket PC app that is set to be the Application form using:
Application.Run(New frmMain())
Somehow this form is getting closed for no reason while working on another form. No closing event is fired and nowhere in my code can you close the main form anyway. It is only closed by clicking the OK button at the top right of the window. When this is clicked, the user is prompted if he/she really wants to close the application. However, this is not occurring either.
Basically, I am on another form which adds a new record to the database. After adding the record the gotFocus event is somehow called for frmMain. When the code in the gotFocus event reaches a reference to a control on the form, there is an exception that states that the object is disposed.
When I bypass the code in the gotFocus event, the application just closes completely. I verify this by checking that it is not running in the device's memory.
I have been stepping through code for 2 hours and I have absolutely no idea why this could be occurring. Anyone possibly have a tip?
This sounds as an exception being raised anywhere. Maybe an exception on another thread? Look at the output window to see what it says.
I'm developing a WinForms app in VB.NET, that handles sets of style data, and when the user clicks on another set's label, it prompts through a dialog "You are leaving this style preset to edit another one. keep changes on this one? [Yes] [No]"
But, I'm facing the problem that, when the user clicks either option, and the dialog closes, everything has to be refreshed, and loading the form again seems a good option.
I've tried putting a public sub on a module, that does this:
Public Sub CloseOpenStyleDlg()
KeepOrDiscardPrompt.Close()
StylesDlg.Close()
StylesDlg.ShowDialog()
End Sub
But as soon as that sub is called from the prompt, it crashes the application. (doesn't show an error in debug, simply crashes) How should I, from a given dialog, close the dialog, it's parent, and re-open it's parent? (which triggers all the Dialog_Load() code of the parent)
Thanks in advance! :)
You need to instantiate the dialog again. If I take your code for example:
Public Sub CloseOpenStyleDlg()
KeepOrDiscardPrompt.Close()
StylesDlg.Close()
StylesDlg = new StylesDlg()
StylesDlg.ShowDialog()
End Sub
When a form is closed, all resources created within the object are closed and the form is disposed.
If you want to reuse the Window instance use StylesDialog.Hide() function instead.