Re: showdialog and 'Cannot access a disposed object'

Chris,

This probably isn't the best way, but it should point you down the right
track. Note in particular that I am populating the hashtable with the type
rather than an instance of it. Then I am pulling out the type, getting its
constructor and calling it to create the type.

Again, there is probably a better way to do this - but I pulled this
together rather quickly.

Option Strict On

Public Class Form1

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Load

        Dim x As New Hashtable

        Call x.Add("Bob", GetType(Class1))

        Dim y As Type = CType(x.Item("Bob"), Type)

        Dim z As System.Reflection.ConstructorInfo =
y.GetConstructor(System.Type.EmptyTypes)

        Dim parameters As Object() = Nothing

        Dim a As Class1 = CType(z.Invoke(parameters), Class1)

        MsgBox(TypeName(a))

    End Sub
End Class

Public Class Class1

End Class

Seeya
Matthew Wills | Solution Designer | Adviser Tools and Services | Financial
Planning and Third Party | NAB Technology

Phone: 02 9376 4029 | Mobile: 0435 002 520 | Email:
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             chris Burgess
             <cbtechlists@GMAI
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             Forms to build            Re: [DOTNET-WINFORMS] showdialog
             apps                      and 'Cannot access a disposed
             and controls              object'
             <DOTNET-WINFORMS@
             DISCUSS.DEVELOP.C
             OM>


             05/01/2008 03:49
             AM


             Please respond to
             Discussion forum
              for developers
               using Windows
              Forms to build
                   apps
               and controls
             <DOTNET-WINFORMS@
             DISCUSS.DEVELOP.C
                    OM>






I think what I really want is to have the report object hold the type
of report form instead of a reference to the actual form object. I
want the button to create a new form each time of the type listed in
the list box/report object, and not reference existing objects.




On Jan 4, 2008 10:53 AM, Peter Ritchie
<[email protected]> wrote:
> On Fri, 4 Jan 2008 09:56:41 -0600, Mike Andrews
> <[email protected]> wrote:
>
> >The issue is that you're creating a new Report via this line:
> >
> >Dim rpt As New BaseReport
> >
> >and then destroying it and in place of it setting an existing one:
> >
> >rpt = DirectCast(Me.Reports.SelectedValue, BaseReport)
> >
> >since the list box contains the references to the report object, and
> you've
> >previously disposed it it will fail to run.
> >You need to refrain from calling the dispose() method until you're done
> with
> >the form in which the listbox resides.
> >You can then dispose all of the reports.
>
> Bingo, the Reports object should be responsible for disposing what it
> aggregates (or the owner of the Reports object if that class doesn't have
> that concept).



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