Question

I need your help to clarify whether form work exactly like object?

If I create an object,obj2, from another object,obj1. the obj2 will be disposed on obj1 dispose.

However it is not so with forms.
check out the case & pseudo code give below.

I have three forms; form1, form2 & form2.

form1 is the startup form.
form1 will create &s how a form2 and from2 will create & show form3 using a button in each form.

if I close form2, after opening all the 3 forms, I am able to work in form1 and form3.

my question is even though form3 is created from form2, why it is not disposed on form2 close?

Form1

---

Public Class Form1
Private Sub cmdOpenForm2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdOpenForm2.Click
  Dim frm As New Form2
  With frm
   ''/.MdiParent = frmMain
   .Show()
   .BringToFront()
  End With
End Sub

 Private Sub Form1_Disposed(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Disposed
  ''//frmMain.tsStatus.Text = "Form1 disposed"
 End Sub
End Class

Form2

---

Public Class Form2
 Private Sub cmdRandomColor_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdRandomColor.Click
  Randomize()
  Label1.ForeColor = Color.FromArgb(Rnd() * 255, Rnd() * 255, Rnd() * 255, Rnd() * 255)
 End Sub

 Private Sub Form2_Disposed(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Disposed
  frmMain.tsStatus.Text = "Form2 disposed"
 End Sub

 Private Sub cmdOpenForm3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdOpenForm3.Click
  Dim frm As New Form3
  With frm
   ''//.MdiParent = frmMain
   .Show()
   .BringToFront()
  End With
 End Sub
 End Class

Form3

---

Public Class Form3
 Private Sub cmdRandomColor_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdRandomColor.Click
  Randomize()
  Label1.ForeColor = Color.FromArgb(Rnd() * 255, Rnd() * 255, Rnd() * 255, Rnd() * 255)
 End Sub

 Private Sub Form3_Disposed(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Disposed
  frmMain.tsStatus.Text = "Form3 disposed"
 End Sub
End Class

Any Help will be greatly appreciated.

EDIT
thank you all for the solution

Sorry to mention, I am not looking for a solution how to do dispose form3 on form2 close.

my interest is what is happening behind… Is there any possibility that form3 instance created from2 get GC collect and i get a memory error.

since i am getting protect memory access exception in my real application, which is not properly designed, and it too big to refactor now.

my question is where the form3 instance created? Is it in Form2 instance or somewhere else.
since i can able to access form3 instance after form2 disposed. i doubt it is created in somewhere else

Answer 1

The framework is still holding on to your form object, until it gets closed. You can get a reference to it using My.Application.OpenForms.