Can MDI Form Inheritance?

[EricDotNet]

I try a Window Form can inheritance,

but MDI Form cannot.

 

Anyone can help me? Thank!

[mutant]

Would you mind explaining your problem a little bit more?

[EricDotNet]

I can inheritance MDI form la,

 

But there are other problems:

I don't want to see a child MDI form is displayed twice.

(i.e. I don't have two instances showing)

 

In parent MDI form, a button click event:

       Dim childForm As frmRefTable

       childForm = childForm.getInstance()
       childForm.MdiParent = Me
       childForm.Show()
       childForm.BringToFront()

 

In Child MDI form,

   Public Shared frmChildForm As frmRefTable

   Public Shared Function getInstance() As frmRefTable
       If frmChildForm Is Nothing Then
           frmChildForm = New frmRefTable
       End If

       Return frmChildForm
   End Function

 

It seem to be work, but when i close the child form and open child form again, Error display:

 

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

 

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