怎么能看网页使用WebBrowser控件 [英] How Can Read Web Page Using WebBrowser control

问题描述

string urlt = webBrowser1.Url.ToString();
Webbrowser1.Navigate("Google.com")

        HtmlElement elem;
        if (webBrowser1.Document != null)
        {
            HtmlElementCollection elems = webBrowser1.Document.GetElementsByTagName("HTML");
            if (elems.Count == 1)
            {
                elem = elems[0];
                string pageSource = elem.InnerHtml;

                if (pageSource == "404" || pageSource == "Inter" || pageSource == "siteblocked")
                {


                }
                else
                {

                    Ret2.Add("Page.." + "Url..." + urlt);

                }

我使用上述code在DocumentCompleted事件看好康但如果我
使用For循环为一个以上的网址，却没有打电话来DocumentCompleted事件每次请建议如果有好主意。

Am Using above mentioned code for reading WebPage at "DocumentCompleted" Event But If I am Using "For loop" for more then one Url It not calling to DocumentCompleted Event everytime Please suggest if any good idea.

推荐答案

从评论：

..但异步或伺机不支持我想到用VS2010 IAM和我
  已安装的NuGet但仍IAM发现异步的关键字，请
  帮助

.. but async or await is not supported i think iam using vs2010 and i already installed Nuget but still iam finding async keyword, please help

如果您不能使用异步/的await ，那么你就不能使用为异步循环 web浏览器导航，除非诉诸去precated与的DoEvents 。使用状态模式，这就是C＃5.0编译器生成幕后为异步/的await 。

If you can't use async/await, then you can't use for loop for asynchronous WebBrowser navigation, unless resorting to deprecated hacks with DoEvents. Use the state pattern, that's what C# 5.0 compiler generates behind the scene for async/await.

另外，如果你有足够的冒险，你可以模拟异步/的await 与收益，描述< A HREF =htt​​p://stackoverflow.com/a/22291625/1768303>这里。

Alternatively, if you're adventurous enough, you can simulate async/await with yield, as described here.

更新，下面是使用C＃枚举状态机的另一种方式（用C＃2.0和更高版本兼容）：

Updated, below is another way of exploiting the C# enumerator state machine (compatible with C# 2.0 and later):

using System;
using System.Collections;
using System.Windows.Forms;

namespace WindowsForms_22296644
{
    public partial class MainForm : Form
    {
        public MainForm()
        {
            InitializeComponent();
        }

        IEnumerable GetNavigator(string[] urls, MethodInvoker next)
        {
            WebBrowserDocumentCompletedEventHandler handler =
                delegate { next(); };

            this.webBrowser.DocumentCompleted += handler;
            try
            {
                foreach (var url in urls)
                {
                    this.webBrowser.Navigate(url);
                    yield return Type.Missing;
                    MessageBox.Show(this.webBrowser.Document.Body.OuterHtml);
                }
            }
            finally
            {
                this.webBrowser.DocumentCompleted -= handler;
            }
        }

        void StartNavigation(string[] urls)
        {
            IEnumerator enumerator = null;
            MethodInvoker next = delegate { enumerator.MoveNext(); };
            enumerator = GetNavigator(urls, next).GetEnumerator();
            next();
        }

        private void Form_Load(object sender, EventArgs e)
        {
            StartNavigation(new[] { 
                "http://example.com",
                "http://example.net",
                "http://example.org" });
        }
    }
}

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