How to disable button from using mdi parent

protectedvoid MDIChildNew_Click(object sender, System.EventArgs e)
                {
                 Form2 newMDIChild = newForm2();
                // Set the Parent Form of the Child window.
                newMDIChild.MdiParent =this;
newMDIChild.Button1.Enabled =  false;
                // Display the new form.
                newMDIChild.Show();
                }