跨线程访问控件的方法

if (lblNum2.InvokeRequired)
                    {
                        lblNum2.Invoke(new Action<string>(s => { this.lblNum2.Text = s; }), Thread.CurrentThread.ManagedThreadId.ToString());
                    }
                    else 
                    {
                        this.lblNum2.Text = Guid.NewGuid().ToString("N");
                    }