Копирование выбранных элементов одного списка в другой

 While (ListBox2.SelectedItems.Count > 0)
            ListBox1.Items.Add(ListBox2.SelectedIndex)
            ListBox2.ClearSelected()
        End While

Me.ListBox2.Items.AddRange(Me.ListBox1.Items)

Me.ListBox2.Items.AddRange(Me.ListBox1.SelectedItems)

Public Class Form1
    Private Sub ExitToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ExitToolStripMenuItem.Click
        Close()
    End Sub
    Private Sub Button4_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button4.Click
        ListBox1.Items.Add(TextBox1.Text)
        TextBox1.Text = ""
    End Sub
    Private Sub TextBox1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress
        If e.KeyChar = Chr(13) Then
            Call Button4_Click_1(sender, e)
            TextBox1.Text = ""
        End If
    End Sub
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        While (ListBox1.SelectedItems.Count > 0)
            ListBox2.Items.Add(ListBox1.SelectedItem)
            ListBox1.Items.RemoveAt(ListBox1.SelectedIndex)
        End While
    End Sub
    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        While (ListBox2.SelectedItems.Count > 0)
            ListBox1.Items.Add(ListBox2.SelectedItem)
            ListBox2.Items.RemoveAt(ListBox2.SelectedIndex)
        End While
    End Sub
    Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
        While (ListBox2.SelectedItems.Count > 0)
            ListBox1.Items.Add(ListBox2.SelectedItem)
 
            ListBox2.ClearSelected()
        End While
    End Sub
    Private Sub Button5_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button5.Click
        While (ListBox1.SelectedItems.Count > 0)
            ListBox2.Items.Add(ListBox1.SelectedItem)
            ListBox1.ClearSelected()
        End While
    End Sub
 
   
End Class

 Private Sub ListBox1_SelectedIndexChanged(sender As System.Object, e As System.EventArgs) Handles ListBox1.SelectedIndexChanged
        ListBox2.Items.Add(ListBox1.SelectedItem)
    End Sub

  Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
        Dim n, i As Integer
        n = ListBox1.SelectedItems.Count
        For i = 0 To n - 1
            ListBox2.Items.Add(ListBox1.SelectedItems.Item(i))
        Next
 
    End Sub