高手帮忙解读一下以下代码，越详细越好

Question

我是菜鸟，看到这些代码不怎么懂，麻烦高手解读一下好么，详细一点噢：        //导出到Excel
        public void ToExcel(System.Web.UI.Control ctl)
        {
            HttpContext.Current.Response.AppendHeader("Content-Disposition", "attachment;filename=Excel.xls");
            HttpContext.Current.Response.Charset = "UTF-8";
            HttpContext.Current.Response.ContentEncoding = System.Text.Encoding.Default;
            HttpContext.Current.Response.ContentType = "application/ms-excel";
            ctl.Page.EnableViewState = false;
            System.IO.StringWriter tw = new System.IO.StringWriter();
            System.Web.UI.HtmlTextWriter hw = new System.Web.UI.HtmlTextWriter(tw);
            ctl.RenderControl(hw);
            HttpContext.Current.Response.Write(tw.ToString());
            HttpContext.Current.Response.End();
        }        //导出到word文档
        public void ToWord(System.Web.UI.Control ctl)
        {
            HttpContext.Current.Response.AppendHeader("Content-Disposition", "attachment;filename=Word.doc");
            HttpContext.Current.Response.Charset = "UTF-8";
            HttpContext.Current.Response.ContentEncoding = System.Text.Encoding.Default;
            HttpContext.Current.Response.ContentType = "application/msword";
            ctl.Page.EnableViewState = false;
            System.IO.StringWriter tw = new System.IO.StringWriter();
            System.Web.UI.HtmlTextWriter hw = new System.Web.UI.HtmlTextWriter(tw);
            ctl.RenderControl(hw);
            HttpContext.Current.Response.Write(tw.ToString());
            HttpContext.Current.Response.End();
        }

Answer 1

 HttpContext.Current.Response.AppendHeader("Content-Disposition", "attachment;filename=Excel.xls");  //输出的格式 filename=Excel.xls输出的名字
            HttpContext.Current.Response.Charset = "UTF-8";//输出的格式
            HttpContext.Current.Response.ContentEncoding = System.Text.Encoding.Default; ";//输出的编码格式
            HttpContext.Current.Response.ContentType = "application/ms-excel";//文档类型 ms-excel为excel
            ctl.Page.EnableViewState = false; //禁用EnableViewState 
            System.IO.StringWriter tw = new System.IO.StringWriter();//写入流
            System.Web.UI.HtmlTextWriter hw = new System.Web.UI.HtmlTextWriter(tw);
            ctl.RenderControl(hw);//写入
            HttpContext.Current.Response.Write(tw.ToString());//输出
            HttpContext.Current.Response.End();//结束当前页的执行

Answer 2

         就一个将控件中的数据导出到Word和Excel中。        //导出到Excel
        public void ToExcel(System.Web.UI.Control ctl)  //方法中的参数是要页面中的控件
        {
            HttpContext.Current.Response.AppendHeader("Content-Disposition", "attachment;filename=Excel.xls"); //为当前上下文中的响应添加头
            HttpContext.Current.Response.Charset = "UTF-8"; //设置响应的字符集
            HttpContext.Current.Response.ContentEncoding = System.Text.Encoding.Default; //响应的内容编码格式
            HttpContext.Current.Response.ContentType = "application/ms-excel"; //内容内省，是ms-excel,说明导出的是Excel格式
            ctl.Page.EnableViewState = false; 
            //以下是利用IO流输出内容
            System.IO.StringWriter tw = new System.IO.StringWriter();  
            System.Web.UI.HtmlTextWriter hw = new System.Web.UI.HtmlTextWriter(tw);
            ctl.RenderControl(hw);
            HttpContext.Current.Response.Write(tw.ToString());
            HttpContext.Current.Response.End();
        }

Answer 3

          HttpContext.Current.Response.ContentType = "application/ms-excel";           HttpContext.Current.Response.ContentType = "application/msword";
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关键在这两句，意思是分别向浏览器输出Excel和Word格式的内容，这样浏览器就不会把内容作为HTML来解析了，而是会在浏览器打开Excel和Word来显示。