MDI親フォームのToolBarを切り替えるには？

	public System.Windows.Forms.ToolBar ToolBar
	{
		get 
		{
			return toolBar1;
		}
	}

	private FormA formA = null;
	private FormB formB = null;
	private FormC formC = null;
	private Form _curForm = null;
	public Form1()
	{
		InitializeComponent();

		formA = new FormA();
		formA.MdiParent = this;
		formA.Show();
		formA.Closing += new System.ComponentModel.CancelEventHandler(this.MdiChild_Closing);

		formB = new FormB();
		formB.MdiParent = this;
		formB.Show();
		formB.Closing += new System.ComponentModel.CancelEventHandler(this.MdiChild_Closing);

		formC = new FormC();
		formC.MdiParent = this;
		formC.Show();
		formC.Closing += new System.ComponentModel.CancelEventHandler(this.MdiChild_Closing);
	}

	private void Form1_MdiChildActivate(object sender, EventArgs e) 
	{
		if (_curForm != null)
		{
			if (_curForm is FormA)
			{
				((FormA) _curForm).ToolBar.Parent = null;
			}
			else if (_curForm is FormB)
			{
				((FormB) _curForm).ToolBar.Parent = null;
			}
			else if (_curForm is FormC)
			{
				((FormC) _curForm).ToolBar.Parent = null;
			}

		}
		if  (this.ActiveMdiChild is FormA)
		{
			_curForm = this.ActiveMdiChild;
			((FormA)_curForm).ToolBar.Parent = panel3;
		}
		else if  (this.ActiveMdiChild is FormB)
		{
			_curForm = this.ActiveMdiChild;
			((FormB)_curForm).ToolBar.Parent = panel3;
		}
		else if  (this.ActiveMdiChild is FormC)
		{
				_curForm = this.ActiveMdiChild;
				((FormC)_curForm).ToolBar.Parent = panel3;
		}
	}

	private bool _forceClose = false;
	private void MdiChild_Closing(object sender, System.ComponentModel.CancelEventArgs e)
	{
		if ( ! _forceClose )
		{
			((Form) sender).Hide();
			e.Cancel = true;
		}

	}

	private void Form1_Closing(object sender, System.ComponentModel.CancelEventArgs e)
	{
		_forceClose = true;
		formA.Close();
		formB.Close();
		formC.Close();
		e.Cancel = false;
	}

	private void toolBar1_ButtonClick(object sender, System.Windows.Forms.ToolBarButtonClickEventArgs e)
	{
		switch (toolBar1.Buttons.IndexOf(e.Button))
		{
			case 0:
				formA.Show();
				formA.Activate();
				break;
			case 1:
				formB.Show();
				formB.Activate();
				break;
			case 2:
				formC.Show();
				formC.Activate();
				break;
		}


	}