Public Class Form1
    Private arr As New ArrayList()
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        If TextBox1.Text <> "" Then
            arr.Add(CInt(TextBox1.Text))
            TextBox1.Text = ""
            TextBox1.Focus()
        End If
    End Sub

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        Dim i As Integer
        For i = 1 To arr.Count
            ListBox1.Items.Add(arr(i - 1))
            TextBox2.Text = arr(i - 1) & vbCrLf
        Next
    End Sub
End Class