[RESOLVED] Problem in Form Activated and Deactivate events (Windows app, .Net 4.0).
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Thread: [RESOLVED] Problem in Form Activated and Deactivate events (Windows app, .Net 4.0).

  1. #1
    Join Date
    Sep 2008
    Posts
    79

    [RESOLVED] Problem in Form Activated and Deactivate events (Windows app, .Net 4.0).

    Scenario
    This is a non-MDI windows application.
    I have a home form containing a panel named Panel1 and two buttons btnForm1 and btnForm2. Clicking btnForm1 and btnForm2 opens up Form1 and Form2 respectively in Panel1. Before a form is opened in Panel1, all opened forms in Panel1 are cleared. The code follows:
    Code:
    Private objForm1 As Form1
    Private Sub btnForm1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnForm1.Click
    	objForm1 = New Form1
    	objForm1.FormBorderStyle = Windows.Forms.FormBorderStyle.None
           objForm1.TopLevel = False
           objForm1.Dock = DockStyle.Fill
    	Panel1.Controls.Clear
    	Panel1.Controls.Add(objForm1)
    	objForm1.Show()
    End Sub
    
    Private Sub btnForm2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnForm2.Click
    	Dim objForm2 As New Form1
    	objForm2.FormBorderStyle = Windows.Forms.FormBorderStyle.None
           objForm2.TopLevel = False
           objForm2.Dock = DockStyle.Fill
    	Panel1.Controls.Clear
    	Panel1.Controls.Add(objForm2)
    	objForm2.Show()
    End Sub
    In Form1 there's a button btnForm3 that opens up Form3 in frmHome.Panel1 just above Form2 without clearing any existing forms in Panel1. This is not done by btnForm3_Click event directly, rather a friend event declared in this form is raised in btnForm3_Click which is handled in frmHome. The code in frmHome to handle it follows:
    Code:
    Private Sub objForm1_LoadForm3InHome() Handles objForm1.LoadSubForm3InHome
    	Dim objForm3 As New Form3
    	objForm3.FormBorderStyle = Windows.Forms.FormBorderStyle.None
           objForm3.TopLevel = False
           objForm3.Dock = DockStyle.Fill
           Panel1.Controls.Add(objForm3)
           objForm3.Show()
           objForm3.BringToFront()
    End Sub
    All the four forms have Add, Edit and Delete buttons among their toolstripbuttons that are common to all of them. They also have File menu among their menuitems that are common to them.

    Objective
    To merge the menu and toolstrip of the currently active form in frmHome.Panel1 to the menu and toolstrip of frmHome. To unmerge the menu and toolstrip of the currently active form in frmHome.Panel1 from the menu and toolstrip of frmHome when the active form of the panel is deactivated. This can be handled by including the undermentioned lines in the form that will open in frmHome.Panel1:
    To merge
    Code:
    ToolStripManager.Merge(Me.MenuStrip1, frmHome.MenuStrip1)
    ToolStripManager.Merge(Me.ToolStrip1, frmHome.ToolStrip1)
    To unmerge
    Code:
    ToolStripManager.RevertMerge(frmHome.MenuStrip1)
    ToolStripManager.RevertMerge(frmHome.ToolStrip1)
    Problem
    In which events should the above lines be written?
    In MDI apps this could have been accomplished by including them in Form_Activated and Form_Deactivate events respectively. But here neither Activated nor Deactivate events fire when you open forms in frmHome.Panel1. Instead of Activated and Deactivate you can use Form_Load and Form_FormClosed events but they will only merge/unmerge menus if existing forms are closed before opening a new form in the panel. But as I sometimes need forms to be opened and closed keeping existing forms opened, using these events won't fulfill the task. Even the GotFocus and LostFocus events won't work. So I want Activated and Deactivate events to be fired or some other means by which the menus and toolstrips can be merged/unmerged when the form gains/looses focus respectively. This is driving me crazy. I can't at all find a way out. Please help. Regards.

  2. #2
    Join Date
    Aug 2009
    Location
    NW USA
    Posts
    173

    Re: Problem in Form Activated and Deactivate events (Windows app, .Net 4.0).

    I'm not tracking all of the form opens and clears but it appears the events that cause a form to show or a panel to clear could also manage the tool strip

  3. #3
    Join Date
    Sep 2008
    Posts
    79

    Smile Re: Problem in Form Activated and Deactivate events (Windows app, .Net 4.0).

    Ok, I worked on it and my conclusion is, the best way to handle this is to use the ControlAdded and ControlRemoved events of the splitcontainer to check which control is currently added/removed and merge/unmerge the toolstrip of that control w.r.t. the Home form toolstrip. Just write a global method to merge/unmerge the toolstrips with a parameter for the name of the control (the control that'll be added/removed in the splitcontainer). In the ControlAdded and ControlRemoved events, call the method with the child control as argument. Refactoring the subforms that I mentioned in the OP to UserControls improved performance but in certain cases they don't fulfill my requirement e.g. when Subform1 is opened in the splitcontainer and Subform3 is opened immediately from it without focusing on any other control of SubForm1 (suppose by clicking a toolstripbutton on SubForm1), unmerging doesn't occur as events like LostFocus, Leave etc are not fired. This creates ambiguity in the menus. So I'll go for the Splitcontainer ControlAdded/ControlRemoved events. But instead of opening forms as child controls I'll henceforth use UserControls.
    I'll drop a small question at the end. How'll I close the UserControl from the SplitContainer panel? Till now I was using:
    Code:
    frmSubForm1.Close()
    frmSubForm1=Nothing
    But UserControls don't have any Close() method.

    Fell free to continue this thread further with your suggestions if needed.

  4. #4
    Join Date
    Sep 2008
    Posts
    79

    Re: Problem in Form Activated and Deactivate events (Windows app, .Net 4.0).

    Invalidate the usercontrol like:
    UserControl.Invalidate()

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