PageFile Usage increasing on every form change

[chrispy102]

Hi all,

I have developed a .Net app in MDI format. The problem that I have is that every time I change screens (New Child), the PC CPU PageFile usage increments a little. This happens until out of memory and I get a System.OutOfMem oryException.

Is there something subtle Im missing when opening/closing MDIChild forms?

I have written a sub to check that only 1 child is open at 1 time and close all child forms, before opening another:

 Public Sub CloseForms()
 
        Dim frm As Form
        Dim Count As Integer
        For Each frm In MDIParent1.MdiChildren
            Count = Count + 1
            frm.Dispose()
        Next
        frm = Nothing
        Count = Nothing
 
    End Sub
 

I also force a garbage collection with every child screen change:
System.GC.Colle ct()

I also wrote a sub to dispose of all controls on each screen every time a form closes:

 Private Sub frmMain_FormClosing(ByVal sender As Object, ByVal e As System.Windows.Forms.FormClosingEventArgs) Handles Me.FormClosing
        Dim FormObject As Control
        For Each FormObject In Me.Controls
            FormObject.Dispose()
        Next
    End Sub

Basically, I got nothing left in the tank, any suggestions would be well recieved!

[Shashi Sadasivan]

instead of disposing each control,
if you rather do

Me.Dispose

it should do the same trick.

however you have put the code in form closing event.
I dont know if it makes any diference compared to if it was put in form_closed event

[Plater]

The dispose method in a form is overloaded to go through all it's child controls and .dipose() them.
However, this doesn't apply to objects that are not gui controls.
Things like filehandles, io streams, sockets, threads and various other objects.
Those must be disposed/closed/aborted manually.
GC.Collect() will not neccesarily do it for you if there is an open handle to it (sockets,stream s, etc) and threads run until their code exits or you call Abort() to send a ThreadAbortExce ption