asp.net开发之输出流的操作步骤
来源：爱站网时间：2020-10-23编辑：网友分享
我们都知道页面的输出后都将变成StringBuilder，当我们处理完StringBuilder之后，响应会重定向到原始页面，接下来爱站技术频道小编为大家带来了asp.net开发之输出流的操作步骤。
我们都知道页面的输出后都将变成StringBuilder，当我们处理完StringBuilder之后，响应会重定向到原始页面，接下来爱站技术频道小编为大家带来了asp.net开发之输出流的操作步骤。
方法的实现原理是：把Response的输出重定向到自定义的容器内，也就是我们的StringBuilder对象里，在HTML所有的向页面输出都变成了向StringBuilder输出，然后我们对StringBuilder处理完成之后，再把Response的输出重定向到原来的页面上，然后再通过Response.Write方法把StringBuilder的内容输出到页面上。
这里之所以用反射，是因为Response对象的OutPut属性是只读的，通过反编译该类的程序集发现，OutPut实际上是内部私有成员 _writer来实现输出的。因此通过反射来改写该成员的值以实现输出流的重定向。
具体功能代码如下：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Text;
using System.IO;
using System.Reflection;
public partial class _Default : System.Web.UI.Page
{
StringBuilder content = new StringBuilder();
TextWriter tw_old, tw_new;
FieldInfo tw_field;
protected void Page_Load(object sender, EventArgs e)
{
var context = HttpContext.Current;
tw_old = context.Response.Output;//Response原来的OutPut
tw_new = new StringWriter(content);//一个StringWriter,用来获取页面内容
var type_rp = context.Response.GetType();
//通过反射获取对象的私有字段
tw_field = type_rp.GetField("_writer", System.Reflection.BindingFlags.Public | System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Instance);
tw_field.SetValue(context.Response, tw_new);
}
protected override void Render(HtmlTextWriter writer)
{
base.Render(writer);
//替换回Response的OutPut
tw_field.SetValue(HttpContext.Current.Response, tw_old);
//做自己的处理
content.AppendLine("");
HttpContext.Current.Response.Write(content.ToString());
}
}
方法二，用HttpModul来实现：
using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.IO; using System.Text; using System.Reflection; //////HttpModule 的摘要说明 /// public class HttpModule : IHttpModule { private HttpApplication _contextApplication; private TextWriter tw_new, tw_old; private StringBuilder _content; private FieldInfo tw_field; public void Init(HttpApplication context) { _contextApplication = context; _contextApplication.PreRequestHandlerExecute += new EventHandler(_contextApplication_PreRequestHandlerExecute); } public void Dispose() { _contextApplication = null; _contextApplication.Dispose(); } public void _contextApplication_PreRequestHandlerExecute(object sender, EventArgs e) { HttpContext context = _contextApplication.Context; var _page = context.Handler as System.Web.UI.Page; _page.Unload += new EventHandler(_page_Unload); _content = new StringBuilder(); tw_old = context.Response.Output;//Response原来的OutPut tw_new = new StringWriter(_content);//一个StringWriter,用来获取页面内容 var type_rp = context.Response.GetType(); tw_field = type_rp.GetField("_writer", System.Reflection.BindingFlags.Public | System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Instance); tw_field.SetValue(context.Response, tw_new); } void _page_Unload(object sender, EventArgs e) { //替换回Response的OutPut tw_field.SetValue(HttpContext.Current.Response, tw_old); //做自己的处理 _content.AppendLine(""); HttpContext.Current.Response.Write(_content.ToString()); } }
方法三：
public class HttpModule : IHttpModule
{
private HttpApplication _contextApplication;
private TextWriter tw_new, tw_old;
private StringBuilder _content;
private FieldInfo tw_field;
public void Init(HttpApplication application)
{
_contextApplication = application;
_contextApplication.BeginRequest += new EventHandler(_contextApplication_BeginRequest);
_contextApplication.EndRequest +=new EventHandler(_contextApplication_EndRequest);
}
void _contextApplication_BeginRequest(object sender, EventArgs e)
{
_content = new StringBuilder();
tw_old = _contextApplication.Response.Output;
tw_new = new StringWriter(_content);
var type_rp = _contextApplication.Response.GetType();
tw_field = type_rp.GetField("_writer", System.Reflection.BindingFlags.Public | System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Instance);
tw_field.SetValue(_contextApplication.Response, tw_new);
}
void _contextApplication_EndRequest(object sender, EventArgs e)
{
tw_field.SetValue(_contextApplication.Response, tw_old);
//做自己的处理
_content.AppendLine("");
_contextApplication.Response.Write(_content.ToString());
}
public void Dispose()
{
_contextApplication = null;
_contextApplication.Dispose();
}
}
通过爱站技术频道小编介绍的asp.net开发之输出流的操作步骤，相信大家都有了很大的了解，小编觉得学习一定要选择好的平台进行学习，这样才能达到事半功倍的效果。
