Getting The Listbox Replacing Item?

Items:

1 listbox
2 textboxes (1 textbox input, 1 textbox edit)
4 buttons (1 button add,1 button remove, 1 button edit, 1 button change)

Private Sub add_Click(sender As System.Object, e As System.EventArgs) Handles add.Click
ListBox1.Items.Clear()'clears the listbox1 before puting the input in
ListBox1.Items.Add(textbox1.text)'This adds what's in the textbox1
End sub

[code]....

this workes but if you test this, you will notice that if you edit the selected item and put it back in it's all the way down again and not at the position as it was.For example:

first item: apples
second item:flowers
third item: orange

so if you edit flowers to pears for example then, will appear below orange.i know i know that this is the issue:

ListBox1.Items.Remove(ListBox1.SelectedItem) 'Removes the item first
ListBox1.SelectedItem = ListBox1.Items.Add(TextBox2.Text)' Add the text thats in textbox2