problems on closing and showing forms (vb.net)

Good day.


Im having a problem in forms. I have a mdi parent form named Main, and a child form named form1.

From Main form, i have a certain menu item that when clicked, it opens form1. But the problem is that when I close form1 and I open it again by accessing the menu, nothing happens.

When I tried to debug it, I put a breakpoint at the menu item

Private sub mnu1_click(byval sender as object, byval e system.args) handles mnu1_click

toform1.show()

End Sub

It generates an error, stating:

An unhandled exception of type 'System.ObjectDisposedException' occurred in system.windows.forms.dll

Additional information: Cannot access a disposed object named "Form1".

This isnt a problem in VB6..

tnx for the help