Styjun

I'm trying to write a web bot which should be undetected so I don't use InnerText property and instead trying to simulate keypresses. To do so I need to focus an <input> element but the focus is switched to another textfield by itself instead even right after element.Focus() call.

I tried also using element.InvokeMember("click"); but it doesn't work either.

public partial class MainForm : Form

 public MainForm()
 
 InitializeComponent();
 

 [DllImport("User32.dll")]
 public static extern int SendMessage(IntPtr hWnd, int uMsg, IntPtr wParam, IntPtr lParam);

 [DllImport("user32.dll", SetLastError = true)]
 static extern IntPtr FindWindowEx(IntPtr hwndParent, IntPtr hwndChildAfter, string lpszClass, string lpszWindow);

 public const Int32 WM_CHAR = 0x0102;
 public const Int32 WM_KEYDOWN = 0x0100;
 public const Int32 WM_KEYUP = 0x0101;
 public const Int32 VK_RETURN = 0x0D;

 IntPtr BrowserHandle
 
 get
 
 var hwnd = _browser.Handle;
 hwnd = FindWindowEx(hwnd, IntPtr.Zero, "Shell Embedding", null);
 hwnd = FindWindowEx(hwnd, IntPtr.Zero, "Shell DocObject View", null);
 hwnd = FindWindowEx(hwnd, IntPtr.Zero, "Internet Explorer_Server", null);
 return hwnd;
 
 

 readonly Random _rnd = new Random();

 private void Form1_Load(object sender, EventArgs e)
 
 _browser.Navigate("https://...");
 _browser.DocumentCompleted += _browser_DocumentCompleted;
 

 private async void _browser_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
 
 if (e.Url.AbsoluteUri != "https://...") return;
 var inputs = _browser.Document.GetElementsByTagName("input");
 
 var el = inputs.OfType<HtmlElement>().FirstOrDefault(x => x.GetAttribute("className").Contains("login"));
 await SendTextAsync(el, "sdfoj30jfoigjdlsgfdgd");
 
 

 async Task SendTextAsync(HtmlElement element, string text)
 
 for (var i = 0; i < text.Length; i++, await Task.Delay(_rnd.Next(0, 500)))
 
 if (_browser.Document.ActiveElement != element)
 
 element.Focus(); // doesn't work
 if (_browser.Document.ActiveElement != element)
 
 element.InvokeMember("click"); // either
 if (_browser.Document.ActiveElement != element)
 
 element.Focus();
 await Task.Delay(_rnd.Next(50, 250)); // anyway
 
 
 

 var c = text[i];
 SendCharacter(c, BrowserHandle);
 
 

 static void SendCharacter(char character, IntPtr hWnd)
 
 var key = new IntPtr(character);
 SendMessage(hWnd, WM_KEYDOWN, key, IntPtr.Zero);
 SendMessage(hWnd, WM_CHAR, key, IntPtr.Zero);
 SendMessage(hWnd, WM_KEYUP, key, IntPtr.Zero);
 

I expected this code to fill the login textfield but instead it writes a few characters there and others go to the password textfield.

The solution is to lookup for element with GetElementsByTagName each time instead of reusing the reference.