Public Sub Button1_Click()
Dim sValue As String = TextArea1.Text
Dim aList As String[] = ListBox1.List
Dim aValues As String[]
If sValue Then
If InStr(sValue, "\n") Then
aValues = Split(sValue, "\n", Null, True)
For i As Integer = 0 To aValues.Max
aList.Push(aValues[i])
Next
ListBox1.List = aList
Else
ListBox1.Add(sValue)
Endif
Endif
End