一个关于xml清空数据的问题
我在代码中点击一下就会生成一个控件，还会把相应的信息以xml的形式保存下来。现在我点这个button点了10下，就意味着创建了10个相对应的xml信息。我把运行程序关掉，再打开再运行，发现之前目录下的xml文件还在。我要在关闭我的程序时加什么代码才能让我的xml文件在程序关闭时清空呢？

public XmlDocument document = new XmlDocument();private void pbBtn_MouseUp(object sender, MouseEventArgs e)

        {  

                if (this.create_Btn)

                {

                    Button button1 = null;

                    button1 = new Button();

                    button1.Width = 80;

                    button1.Height = 35;

                    button1.Name = "Button" + BtnCount;

                    button1.AutoSize = true;

                    button1.Text = "Button" + BtnCount;

                    button1.Location = new Point(e.X - 108, e.Y + 30);

                    button1.MouseDown += new System.Windows.Forms.MouseEventHandler(Button_MouseDown);

                    button1.MouseMove += new System.Windows.Forms.MouseEventHandler(Button_MouseMove);

                    button1.MouseUp += new System.Windows.Forms.MouseEventHandler(Button_MouseUp);

                    button1.MouseLeave += new System.EventHandler(MyMouseLeave);

                    button1.Enter += new System.EventHandler(BtnEnter);

                    button1.KeyDown += new KeyEventHandler(MykeyDown);

                    button1.KeyUp += new KeyEventHandler(MykeyUp);

                    button1.Cursor = System.Windows.Forms.Cursors.Default;

                    this.panel1.Controls.Add(button1); 

                    this.listbtn.Add(button1);

&n