How to open a new instance of a form closing the old one

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I have created two forms

1. form1
2. form2

i made form1 's ismdicontainer is true
i created a button in form1 and in that button i wrote
following codes to open form2

dim x as new form2
x.showDialog()

In form2 I have designed a calculator and i have put a new button
in that button (new calculation) i have written to create a new instance of the calculator
as follows

dim x as new form2
x.showDialog()

it is working fine but it is not closing the old instance.
if i do it more than 10 or 15 times it shows overload error.
what i want is that if i click on new calculation button it should close the old instance and start the new instance

What I have tried:

i have tried following codes but it is not closing old instance

me.close()
dim x as new form2
x.showDialog()

also i have tried following codes still it is not closing the old instance

dim x as new form2
x.showDialog()
me.close()

Posted 15-Jan-18 4:38am

CodeMine

Updated 30-Nov-20 16:26pm

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2 solutions

Solution 1

insted of me.close()
try

Me.Hide()

Posted 15-Jan-18 5:06am

Dotnet_Dotnet

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Dave Kreskowiak · Accepted Answer · 2018-01-15T05:18:00

You cannot do what you want. Windows are opened in a hierarchy, not a chain.

The first form shown is the top of the window tree. Closing it closes your entire application.

The parent window can HIDE itself. It cannot close itself if there are child windows.

GrandParent Window
        |
        |
  Parent Window
        |
        |
   Child Window

If you want the new child window to replace the parent. The parent window must not create the child window. The GRANDPARENT window should create the new window to replace the parent window.

       GrandParent Window
               |
     ----------+------------------
     |                           |
Parent Window          New Parent Window

Oh! And any form you show with ShowDialog() MUST have Dispose() called on it before its reference goes out of scope.

Dim x As New Form2
result = x.ShowDialog()
x.Dispose()