StrataFrame Forum » StrataFrame Application Framework - V1 » WinForms (How do I?) » How to show a form that needs to be hidden immediately.

How to show a form that needs to be hidden immediately.

Greg McGuffey — Wed, 17 Dec 2008 11:43:41 GMT

I have a form that I'd like to load, but have it hidden immediately. I'm currently just setting visible to False after it's done loading, but there is flicker. Is there a suggested way to do this.

RE: How to show a form that needs to be hidden immediately.

Greg McGuffey — Wed, 17 Dec 2008 11:43:41 GMT

Just noticed that I never let y'all know what I actually did. I ended up adding a method to the form to show the browse dialog, then if the dialog returns OK, show the form. Sort of a combo between what I was trying and what Trent suggested:

[codesnippet]' In the form that I wanted hidden...
Public Sub Search()
  ' Open search form, test for OK
  Using myBrw As New MyBrowseDialog()
    If myBrw.ShowDialog() = DialogResult.OK Then
      Me.Show()
    Else
      Me.Close
    End If
  End Using
End Sub[/codesnippet]

And it is called like this
[codesnippet]' To run a search...
Dim frm As New MyForm()
frm.Search()[/codesnippet]

RE: How to show a form that needs to be hidden immediately.

Trent L. Taylor — Tue, 09 Sep 2008 10:03:07 GMT

When I have the need for this, I take a different approach. First, show the BrowseDialog THEN show the form. It would look something like this:

[codesnippet]Dim myBrw As New MyBrowseDialog()
Dim myBO As New MyBO()
Dim myForm as MyForm

'-- Set the BO to populate (otherwise an error will occur)
myBrw.BusinessObjectToPopulate = myBO

'-- Show the Browse
If myBrw.ShowDialog() = OK Then
    '-- Create and show the form. Pass over the populated BO and then just do a CopyDataFrom in the Constructor
    '-- of the form.
    myForm = New MyForm(myBO)

'-- Now show the dialog or show it in your MDI (whatever your need is)
myForm.ShowDialog()
End If[/codesnippet]

RE: How to show a form that needs to be hidden immediately.

Greg McGuffey — Thu, 04 Sep 2008 13:47:39 GMT

Nope, that won't work as this is being called in a class that isn't a form at all. :pinch:

I've also tried:

- setting the location off the screen (-3200,-3200)
- setting the size to zero
- locking the MDI parent form using ScreenLock
- minimizing the form
- calling visible before show
- Hiding the form in the VisibleChanged event

Nothing worked. In every case, there is a brief moment when the form is shown before going away.

I'm still curious if this can be done, so if anyone has any thoughts I'd love to hear them!

However, my understanding of garbage collection wasn't complete. I assumed that the parent form would stick around after the search form was closed. Then I got the brilliant idea to actually test this and put a breakpoint in the dispose method (hey what can I say...apparently both brain cells are active today). Turns out that when the search form is closed, before the main form has been shown, it is disposed of immediately! There was no problem to solve! DOH! :pinch:

Thanks for your help though, Edhy. It did get me thinking, which lead to some google searches that lead to the other brain cell firing. :w00t:

RE: How to show a form that needs to be hidden immediately.

Edhy Rijo — Thu, 04 Sep 2008 12:50:14 GMT

What about something like this:

[codesnippet]

Public Shared Sub OpenMyForm(ByVal projectID As Integer)

MicroFour.StrataFrame.Tools.LockScreen.Lock(Me)

Dim frm As New MyForm(projectID)

frm.MDIParent = MainForm

frm.Visible = False

MicroFour.StrataFrame.Tools.LockScreen.Unlock()

' This method on the form calls the search form

frm.Search()

End Sub

[/codesnippet]

RE: How to show a form that needs to be hidden immediately.

Greg McGuffey — Thu, 04 Sep 2008 12:35:56 GMT

Well, I'm probably even more confused. Here's what I'm trying to do:

I've written my own "browse" dialog (long story) and want to be able to open a form, show that dialog, not the form. The user then does a search, selects one or more records and clicks a "view" button. At this point my form loads those records into its BO and is shown.

However, I needed to handle the case were the user closes the search form before selecting any records to open. My concern was that if I didn't show the form, it wouldn't get garbage collected. I'm using code like this to open the form:

[codesnippet]Public Shared Sub OpenMyForm(projectID as integer)
Dim frm As New MyForm(projectID)
frm.MDIParent = MainForm
' This method on the form calls the search form
frm.Search()
End Sub[/codesnippet]

I was originally just showing my search dialog before I'd loaded the form (before the Show() method had been called). Maybe this is OK?

RE: How to show a form that needs to be hidden immediately.

Edhy Rijo — Thu, 04 Sep 2008 12:20:57 GMT

Greg,

I am a bit confused here, when you create the instance of the form, it is not visible, so you should have access to it before you set it form.Visible = True.

Also the lock method are to be work not in the form itself, but in the calling class where you are creating your form, so it will lock that view, your form will be created, then will unlock the previous locked view.

How are you calling your form?

RE: How to show a form that needs to be hidden immediately.

Greg McGuffey — Thu, 04 Sep 2008 12:15:51 GMT

Thanks Edhy. I didn't know that one existed (or forgot about it).

It's not working though. Here is the code that I tried. It still shows the form, at least the outline of it before it is hidden.

[codesnippet]MicroFour.StrataFrame.Tools.LockScreen.Lock(Me)
Me.Show()
Me.Visible = False
MicroFour.StrataFrame.Tools.LockScreen.UnLock()[/codesnippet]

Any other ideas?

RE: How to show a form that needs to be hidden immediately.

Edhy Rijo — Wed, 03 Sep 2008 20:31:58 GMT

Hi Greg,

How about wrapping your code with a LockScreen:

[codesnippet]

MicroFour.StrataFrame.Tools.LockScreen.Lock(Me)

... Your code

MicroFour.StrataFrame.Tools.LockScreen.UnLock()

[/codesnippet]