Form1.cs

#region Copyright

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// 
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// modification, must retain the above copyright notice and the following
// disclaimer.
// 
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#endregion

using System;
using System.IO;
using System.Windows.Forms;
using DotNetBrowser.Browser;
using DotNetBrowser.Dom;
using DotNetBrowser.Engine;
using DotNetBrowser.Js;

namespace ElementVisibility.WinForms
{
    /// <summary>
    ///     This example demonstrates how to change DOM element visibility
    ///     by modifying its CSS style.
    /// </summary>
    public partial class Form1 : Form
    {
        private readonly IBrowser browser;
        private readonly IEngine engine;

        public Form1()
        {
            engine = EngineFactory.Create(new EngineOptions.Builder
            {
                RenderingMode = RenderingMode.HardwareAccelerated
            }.Build());

            browser = engine.CreateBrowser();
            InitializeComponent();
            browserView1.InitializeFrom(browser);

            browser.Navigation.LoadUrl(Path.GetFullPath("index.html"));
        }

        private void ChangeImageVisibility(object sender, EventArgs e)
        {
            IDocument document = browser.MainFrame.Document;

            // Find element on the loaded web page.
            IElement img = document.GetElementById("img");

            // Transform it into JsObject.
            IJsObject imgObject = img as IJsObject;

            // Apply the desired style.
            IJsObject style = imgObject.Properties["style"] as IJsObject;

            if (style.Properties["display"].ToString() != "none")
            {
                style.Properties["display"] = "none";
            }
            else
            {
                style.Properties["display"] = "inline";
            }
        }

        private void Form1_FormClosed(object sender, FormClosedEventArgs e)
        {
            engine?.Dispose();
        }
    }
}