VB Listbox change value

How can i change a value in a VB Listbox?

Like this it doesn't work:

listbox.selectedItem = "Newvalue"

THX fo开发者_开发百科r help

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listbox.List(listbox.ListIndex) = "NewValue"

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Adding items to listbox:

ListBox1.Items.Add("AA")
ListBox1.Items.Add("BB")
ListBox1.Items.Add("CC")
ListBox1.Items.Add("DD")

now select anyone 1 option in the listbox:

Add this code in your button click

ListBox1.SelectedItem.Text = "newvalue"

the selected option/value "CC" is changed to "newvalue"