gecko browser button click doesn't work c#

Question

I'm tiring to emulate the google search with gecko web browser. so far i have able to go to the google page and then search some thing like this:

    geckoWebBrowser1.Navigate("https://www.google.com/");
    await Task.Run(() => CheckDocumentLoaded());

    var page = geckoWebBrowser1.Document.GetElementById("lst-ib");
    (page as GeckoHtmlElement).Focus();
    (page as GeckoInputElement).Value = "something";

now i simply want to click on the search button. so i added this to the first part:

    var button = new GeckoButtonElement(geckoWebBrowser1.Document.GetElementById("mKlEF").DomObject);
    button.Click();

but funny things happens. if i run this code after the first part nothing will happens. but if i created a button and put the code on it it works just fine.

private void Button1_Click(object sender, EventArgs e)
{
    var button = new GeckoButtonElement(geckoWebBrowser1.Document.GetElementById("mKlEF").DomObject);
    button.Click();

    return;
}

but i have to click on button manually in order to make it work. its really confusing. i have no idea what causes this!!

NOTE:

1. you have to use this user agent if you want to the code works: (Mozilla/5.0 (Windows NT 10.0; WOW64; Trident/7.0; rv:11.0) like Gecko)

2. i don't want to use the SendKeys.Send("{ENTER}").

3. if i press the button programmatically its not work either.

Answer 1

I played around and recreated your scenario in a WPF app.

I got it working using the DocumentCompleted event that

occurs after the browser has finished parsing a new page and updated the Document property.

I subscribe to the event listener before navigation and remove it once the handler is invoked.

Then, I call the first element of the form to submit the search.

(_browser.Document.GetElementsByTagName("form").First() as GeckoFormElement).submit();

Full code sample: WPF app

using Gecko;
using Gecko.DOM;
using System.Windows;
using System.Windows.Forms.Integration;
using System.Linq;    
namespace GeckoWpf {
    public partial class MainWindow : Window {
        public MainWindow() {
            InitializeComponent();
            Gecko.Xpcom.Initialize("Firefox");
        } 

        void browser_DocumentCompleted(object sender, System.EventArgs e) {
             //unsubscribe
            _browser.DocumentCompleted -= browser_DocumentCompleted;

            XPathResult xpathResult = _browser.Document.EvaluateXPath("//div/input");
            var foundNodes = xpathResult.GetNodes();
            foreach (var node in foundNodes) {
                GeckoInputElement txtbox = new GeckoInputElement(node.DomObject);
                txtbox.Value = "Mona Lisa"; //add the search term
            }    
            (_browser.Document.GetElementsByTagName("form").First() as GeckoFormElement).submit();
        }

        WindowsFormsHost _host = new WindowsFormsHost();
        GeckoWebBrowser _browser = new GeckoWebBrowser();    
        private void Window_Loaded(object sender, RoutedEventArgs e) {
            _browser.DocumentCompleted += browser_DocumentCompleted;
            _host.Child = _browser;    GridWeb.Children.Add(_host);    
            _browser.Navigate("https://www.google.com/");
        }
    }
}

Note: This approach may not work on all pages since DocumentComplete may get fired multiple times for various reasons (e.g. i/frames, AJAX and other dynamic stuff).

PS: Nonetheless, your endeavor may or may not be legal.
You may want to consider using Google's custom search API or alternatives like SerpApi instead.