本文主要讲解通过WebBrowser控件打开浏览页面,并操作页面元素实现自动搜索功能,仅供学习分享使用,如有不足之处,还请指正。
涉及知识点
- WebBrowser:用于在WinForm窗体中,模拟浏览器,打开并导航网页。
- HtmlDocument:表示一个Html文档的页面。每次加载都会是一个全新的页面。
- GetElementById(string id):通过ID或Name获取一个Html中的元素。
- HtmlElement:表示一个Html标签元素。
- BackgroundWorker 后台执行独立操作的进程。
设计思路
主要采用异步等待的方式,等待页面加载完成,流程如下所示:
示例效果图
如下所示:加载完成后,自动输入【天安门】并点击搜索。
核心代码
加载新的页面,如下所示:
string url = "https://www.so.com/"; this.wb01.ScriptErrorsSuppressed = true; this.wb01.Navigate(url);
注意:this.wb01.ScriptErrorsSuppressed = true;用于是否弹出异常脚本代码错误框
获取元素并赋值,如下所示:
string search_id = "input"; string search_value = "天安门"; string btn_id = "search-button"; HtmlDocument doc = this.wb01.Document; HtmlElement search = doc.GetElementById(search_id); search.SetAttribute("value", search_value); HtmlElement btn = doc.GetElementById(btn_id); btn.InvokeMember("click");
示例整体代码,如下所示:
using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Threading; using System.Threading.Tasks; using System.Windows.Forms; namespace DemoExplorer { public partial class FrmExplorer : Form { private bool isLoadOk = false; private BackgroundWorker bgWork; public FrmExplorer() { InitializeComponent(); } private void FrmExplorer_Load(object sender, EventArgs e) { bgWork = new BackgroundWorker(); bgWork.DoWork += bgWork_DoWork; bgWork.RunWorkerCompleted += bgWork_RunWorkerCompleted; string url = "https://www.so.com/"; this.wb01.ScriptErrors<span style="color:transparent">来1源gaodai#ma#com搞*代#码1网</span>Suppressed = true; this.wb01.Navigate(url); bgWork.RunWorkerAsync(); } private void bgWork_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e) { string search_id = "input"; string search_value = "天安门"; string btn_id = "search-button"; HtmlDocument doc = this.wb01.Document; HtmlElement search = doc.GetElementById(search_id); search.SetAttribute("value", search_value); HtmlElement btn = doc.GetElementById(btn_id); btn.InvokeMember("click"); } private void bgWork_DoWork(object sender, DoWorkEventArgs e) { compWait(); } private void compWait() { while (!isLoadOk) { Thread.Sleep(500); } } private void wb01_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e) { this.wb01.Document.Window.Error += new HtmlElementErrorEventHandler(Window_Error); if (this.wb01.ReadyState == WebBrowserReadyState.Complete) { isLoadOk = true; } else { isLoadOk = false; } } private void Window_Error(object sender, HtmlElementErrorEventArgs e) { e.Handled = true; } } }