VB.NETでのフォーム遷移について

' メインクラス
Public Class Class1

    Public Shared WithEvents F1 As Form1
    Public Shared WithEvents F2 As Form2
    Public Shared WithEvents F3 As Form3

    Private Shared Counter As Integer = 0

    Private Sub New()
        F1 = New Form1
        F1.Show()
        Application.Run()
    End Sub

    Public Shared Sub Main()
        Dim C1 As Class1 = New Class1
    End Sub

    Private Shared Sub Form_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles F1.Load, F2.Load, F3.Load
        Counter += 1
    End Sub

    Private Shared Sub Form_Closed(ByVal sender As Object, ByVal e As System.EventArgs) Handles F1.Closed, F2.Closed, F3.Closed
        Counter -= 1

        If Counter.Equals(0) Then
            Application.Exit()
        End If
    End Sub

End Class

' フォーム
Public Class Form1
    Inherits System.Windows.Forms.Form

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Class1.F2 = New Form2
        Class1.F2.Show()
        Me.Close()
    End Sub
End Class

class MyApplicationContext : ApplicationContext 

{

	private Form1 form1;

	private Form2 form2;



	private MyApplicationContext() 

	{

		form1 = new Form1();

		form1.Closed += new EventHandler(OnFormClosed);            

		form1.Show();

	}



	private void OnFormClosed(object sender, EventArgs e) 

	{

		if (sender is Form1) 

		{

			form2 = new Form2();

			form2.Closed += new EventHandler(OnFormClosed);

			form2.Show();

		}

		else if (sender is Form2) 

		{

			ExitThread();

		}



	}



	[STAThread]

	static void Main() 

	{

		MyApplicationContext context = new MyApplicationContext();

		Application.Run(context);

	}

}