VB.net modifying a form from another form

I have a main form called MainScreen. I have a listbox in this MainScreen that I am trying to update from another form(form2). I am clicking a button in form2, and I want it to add something to the listbox in MainScreen. I have tried just doing MainScreen.listbox.items.add("FFFF"), but that doesn't seem to work. I have also tried creating variables of type MainScreen and doing it that way, but I get an error(Object reference not set to an instance of an object). I have also tried creating a function in MainScreen:
    Public Sub AddItemToList(ByVal listitem As String)
    mylistbox.item.add(listitem)
    End Sub
and calling that function from form2, but get that same error.

Should I be making MainScreen the parent of form2 somehow? Any help would be appreciated.
dnk99Asked:
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DabasCommented:
Hi dnk99,
I assume that somewhere in MainScreen you have something like this:

Dim f as new Form2
f.Show

To solve your problem, you need to add two lines to your program.

In form2, add the following line:

Public fMainScreen as MainScreen

In MainScreen, add the following line before f.Show:

f.FMainScreen = Me

Now you will be able to do what you want:

fMainScreen.ListBox.Items.Add("FFFF")

Dabas
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dnk99Author Commented:
Thanks Dabas. Works perfectly.
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