using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

//新添加命名空间
using System.Net;
using System.IO;

namespace HttpWeb
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        //双击"浏览"添加Click事件
        private void button1_Click(object sender, EventArgs e)
        {
            //获取输入的URL
            string url = textBox1.Text;
            //string url = "http://mail.163.com/";

            //创建http链接
            //HttpWebRequest对象实例:该类用于获取和操作HTTP请求 var可改成HttpWebRequest
            var request = (HttpWebRequest)WebRequest.Create(url);   //创建WebRequest对象

            //HttpWebResponse对象实例:该类用于获取和操作HTTP应答 var可改成HttpWebResponse
            var response = (HttpWebResponse)request.GetResponse();  //GetResponse:获取答复

            //构造数据流对象实例
            Stream stream = response.GetResponseStream();  //GetResponseStream:获取应答流
            StreamReader sr = new StreamReader(stream);    //从字节流中读取字符

            //从流当前位置读取到末尾并显示在WebBrower控件中
            string content = sr.ReadToEnd();
            webBrowser1.DocumentText = content;
        }

        //web浏览器控件中承载的文档全部加载后发生
        private void webBrowser1_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
        {
            //定义html元素 通过Name获取控件值
            //HtmlElement tbUserid = webBrowser1.Document.All["userName"];
            //HtmlElement tbPasswd = webBrowser1.Document.All["password"];
            
            //定义html元素 通过ID获取控件值 (用户名 密码 登录按钮)
            HtmlElement tbUserid = webBrowser1.Document.GetElementById("idInput");
            HtmlElement tbPasswd = webBrowser1.Document.GetElementById("pwdInput");
            HtmlElement btnSubmit = webBrowser1.Document.GetElementById("loginBtn");

            //三个元素其一为空返回 加载后才执行赋值 否则会出现为null值的崩溃错误
            if (tbUserid == null || tbPasswd == null || btnSubmit == null)
            {
                return;
            }
            
            //设置元素value属性值 (用户名 密码值)
            tbUserid.SetAttribute("value", "Eastmount");
            tbPasswd.SetAttribute("value", "Eastmount");
            
            //执行元素的方法：如click submit
            btnSubmit.InvokeMember("click");     
        }
    }
}

//获取网页元素 (用户名 密码 登录按钮)
HtmlElement tbUserid = webBrowser1.Document.GetElementById("idInput");
HtmlElement tbPasswd = webBrowser1.Document.GetElementById("pwdInput");
HtmlElement btnSubmit = webBrowser1.Document.GetElementById("loginBtn");

//用相应方法为元素赋值
tbUserid.SetAttribute("value", "Eastmount");
tbPasswd.SetAttribute("value", "Eastmount");
btnSubmit.InvokeMember("click");