C＃WebBrowser控件 - 表單提交不工作使用InvokeMember（「Click」）

Question

我正在使用自動化測試腳本，並使用WebBrowser控件。我想，當用戶接受服務條款的規定提交以下HTML和測試：

<form action="http://post.dev.dealerconnextion/k/6hRbDTwn4xGVl2MHITQsBw/hrshq" method="post"> 
     <input name="StepCheck" value="U2FsdGVkX18zMTk5MzE5OUgFyFgD3V5yf5Rwbtfhf3gjdH4KSx4hqj4vkrw7K6e-" type="hidden"> 
     <button type="submit" name="continue" value="y">ACCEPT the terms of use</button> 
     <button type="submit" name="continue" value="n">DECLINE the terms of use</button> 
    </form> 

    // Terms of Use Information 

    <form action="http://post.dev.dealerconnextion/k/6hRbDTwn4xGVl2MHITQsBw/hrshq" method="post"> 
     <input name="StepCheck" value="U2FsdGVkX18zMTk5MzE5OUgFyFgD3V5yf5Rwbtfhf3gjdH4KSx4hqj4vkrw7K6e-" type="hidden"> 
     <button type="submit" name="continue" value="y">ACCEPT the terms of use</button> 
     <button type="submit" name="continue" value="n">DECLINE the terms of use</button> 
    </form> 

下面是C＃代碼，但不提交表單。

  HtmlElementCollection el = webBrowser.Document.GetElementsByTagName("button"); 
      foreach (HtmlElement btn in el) 
      { 
       if (btn.InnerText == "ACCEPT the terms of use") 
       { 
        btn.InvokeMember("Click"); 
       } 
      } 

任何幫助將不勝感激。謝謝。

Answer 1

以下代碼適用於我，使用IE10測試的問題註釋中的實時表單操作URL。試試看。如果它也適用於您，請隨時將其用作Web自動化任務的模板。幾個要點：

• FEATURE_BROWSER_EMULATION用於確保WebBrowser的行爲以同樣的方式作爲獨立的IE瀏覽器（或儘量接近）。 對於幾乎任何WebBrowser的項目，這是必須的。我相信這應該有助於解決原來的問題。

• 異步代碼用於提高自動化邏輯的可靠性，增加支持超時和取消並促進自然線性代碼流（使用async/await）。

C＃：

using Microsoft.Win32; 
using System; 
using System.Diagnostics; 
using System.Linq; 
using System.Threading; 
using System.Threading.Tasks; 
using System.Windows.Forms; 

namespace WebAutomation 
{ 
    // http://stackoverflow.com/q/19044659/1768303 

    public partial class MainForm : Form 
    { 
     WebBrowser webBrowser; 

     // non-deterministic delay to let AJAX code run 
     const int AJAX_DELAY = 1000; 

     // keep track of the main automation task 
     CancellationTokenSource mainCts; 
     Task mainTask = null; 

     public MainForm() 
     { 
      SetBrowserFeatureControl(); // set FEATURE_BROWSER_EMULATION first 

      InitializeComponent(); 

      InitBrowser(); 

      this.Load += (s, e) => 
      { 
       // start the automation when form is loaded 
       // timeout the whole automation task in 30s 
       mainCts = new CancellationTokenSource(30000); 
       mainTask = DoAutomationAsync(mainCts.Token).ContinueWith((completedTask) => 
       { 
        Trace.WriteLine(String.Format("Automation task status: {0}", completedTask.Status.ToString())); 
       }, TaskScheduler.FromCurrentSynchronizationContext()); 
      }; 

      this.FormClosing += (s, e) => 
      { 
       // cancel the automation if form closes 
       if (this.mainTask != null && !this.mainTask.IsCompleted) 
        mainCts.Cancel(); 
      }; 
     } 

     // create a WebBrowser instance (could use an existing one) 
     void InitBrowser() 
     { 
      this.webBrowser = new WebBrowser(); 
      this.webBrowser.Dock = DockStyle.Fill; 
      this.Controls.Add(this.webBrowser); 
      this.webBrowser.Visible = true; 
     } 

     // the main automation logic 
     async Task DoAutomationAsync(CancellationToken ct) 
     { 
      await NavigateAsync(ct,() => this.webBrowser.Navigate("http://localhost:81/test.html"), 10000); // timeout in 10s 
      // page loaded, log the page's HTML 
      Trace.WriteLine(GetBrowserDocumentHtml()); 

      // do the DOM automation 
      HtmlElementCollection all = webBrowser.Document.GetElementsByTagName("button"); 
      // throw if none or more than one element found 
      HtmlElement btn = all.Cast<HtmlElement>().Single(
       el => el.InnerHtml == "ACCEPT the terms of use"); 

      ct.ThrowIfCancellationRequested(); 

      // simulate a click which causes navigation 
      await NavigateAsync(ct,() => btn.InvokeMember("click"), 10000); // timeout in 10s 

      // form submitted and new page loaded, log the page's HTML 
      Trace.WriteLine(GetBrowserDocumentHtml()); 

      // could continue with another NavigateAsync 
      // othrwise, the automation session completed 
     } 

     // Get the full HTML content of the document 
     string GetBrowserDocumentHtml() 
     { 
      return this.webBrowser.Document.GetElementsByTagName("html")[0].OuterHtml; 
     } 

     // Async navigation 
     async Task NavigateAsync(CancellationToken ct, Action startNavigation, int timeout = Timeout.Infinite) 
     { 
      var onloadTcs = new TaskCompletionSource<bool>(); 
      EventHandler onloadEventHandler = null; 

      WebBrowserDocumentCompletedEventHandler documentCompletedHandler = delegate 
      { 
       // DocumentCompleted may be called several time for the same page, 
       // beacuse of frames 
       if (onloadEventHandler != null || onloadTcs == null || onloadTcs.Task.IsCompleted) 
        return; 

       // handle DOM onload event to make sure the document is fully loaded 
       onloadEventHandler = (s, e) => 
        onloadTcs.TrySetResult(true); 
       this.webBrowser.Document.Window.AttachEventHandler("onload", onloadEventHandler); 
      }; 

      using (var cts = CancellationTokenSource.CreateLinkedTokenSource(ct)) 
      { 
       if (timeout != Timeout.Infinite) 
        cts.CancelAfter(Timeout.Infinite); 

       using (cts.Token.Register(() => onloadTcs.TrySetCanceled(), useSynchronizationContext: true)) 
       { 
        this.webBrowser.DocumentCompleted += documentCompletedHandler; 
        try 
        { 
         startNavigation(); 
         // wait for DOM onload, throw if cancelled 
         await onloadTcs.Task; 
         ct.ThrowIfCancellationRequested(); 
         // let AJAX code run, throw if cancelled 
         await Task.Delay(AJAX_DELAY, ct); 
        } 
        finally 
        { 
         this.webBrowser.DocumentCompleted -= documentCompletedHandler; 
         if (onloadEventHandler != null) 
          this.webBrowser.Document.Window.DetachEventHandler("onload", onloadEventHandler); 
        } 
       } 
      } 
     } 

     // Browser feature conntrol 
     void SetBrowserFeatureControl() 
     { 
      // http://msdn.microsoft.com/en-us/library/ee330720(v=vs.85).aspx 

      // FeatureControl settings are per-process 
      var fileName = System.IO.Path.GetFileName(Process.GetCurrentProcess().MainModule.FileName); 

      // make the control is not running inside Visual Studio Designer 
      if (String.Compare(fileName, "devenv.exe", true) == 0 || String.Compare(fileName, "XDesProc.exe", true) == 0) 
       return; 

      SetBrowserFeatureControlKey("FEATURE_BROWSER_EMULATION", fileName, GetBrowserEmulationMode()); // Webpages containing standards-based !DOCTYPE directives are displayed in IE10 Standards mode. 
     } 

     void SetBrowserFeatureControlKey(string feature, string appName, uint value) 
     { 
      using (var key = Registry.CurrentUser.CreateSubKey(
       String.Concat(@"Software\Microsoft\Internet Explorer\Main\FeatureControl\", feature), 
       RegistryKeyPermissionCheck.ReadWriteSubTree)) 
      { 
       key.SetValue(appName, (UInt32)value, RegistryValueKind.DWord); 
      } 
     } 

     UInt32 GetBrowserEmulationMode() 
     { 
      int browserVersion = 7; 
      using (var ieKey = Registry.LocalMachine.OpenSubKey(@"SOFTWARE\Microsoft\Internet Explorer", 
       RegistryKeyPermissionCheck.ReadSubTree, 
       System.Security.AccessControl.RegistryRights.QueryValues)) 
      { 
       var version = ieKey.GetValue("svcVersion"); 
       if (null == version) 
       { 
        version = ieKey.GetValue("Version"); 
        if (null == version) 
         throw new ApplicationException("Microsoft Internet Explorer is required!"); 
       } 
       int.TryParse(version.ToString().Split('.')[0], out browserVersion); 
      } 

      UInt32 mode = 10000; // Internet Explorer 10. Webpages containing standards-based !DOCTYPE directives are displayed in IE10 Standards mode. Default value for Internet Explorer 10. 
      switch (browserVersion) 
      { 
       case 7: 
        mode = 7000; // Webpages containing standards-based !DOCTYPE directives are displayed in IE7 Standards mode. Default value for applications hosting the WebBrowser Control. 
        break; 
       case 8: 
        mode = 8000; // Webpages containing standards-based !DOCTYPE directives are displayed in IE8 mode. Default value for Internet Explorer 8 
        break; 
       case 9: 
        mode = 9000; // Internet Explorer 9. Webpages containing standards-based !DOCTYPE directives are displayed in IE9 mode. Default value for Internet Explorer 9. 
        break; 
       default: 
        // use IE10 mode by default 
        break; 
      } 

      return mode; 
     } 
    } 
} 

的http://localhost:81/test.html內容：在`DocumentCompleted`事件

<!DOCTYPE html> 
<head> 
<meta http-equiv="X-UA-Compatible" content="IE=edge"/> 
</head> 
<body> 
    <form action="<the URL from OP's comments>" method="post"> 
     <input name="StepCheck" value="U2FsdGVkX18zMTk5MzE5OUgFyFgD3V5yf5Rwbtfhf3gjdH4KSx4hqj4vkrw7K6e-" type="hidden"> 
     <button type="submit" name="continue" value="y">ACCEPT the terms of use</button> 
     <button type="submit" name="continue" value="n">DECLINE the terms of use</button> 
    </form> 
</body>