using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using CefSharp;
using CefSharp.WinForms;
using System.Configuration;

namespace VR.Winfrom
{
    public partial class Form1 : Form
    {
        public ChromiumWebBrowser chromeBrowser;

        public Form1()
        {
            InitializeComponent();
            this.WindowState = FormWindowState.Maximized;
            InitializeChromium();
            // Register an object in javascript named "cefCustomObject" with function of the CefCustomObject class :3
            chromeBrowser.RegisterJsObject("formProcess", new FormProcess(chromeBrowser, this));
        }

        public void InitializeChromium()
        {
            CefSettings settings = new CefSettings();
            // Initialize cef with the provided settings
            Cef.Initialize(settings);
            // Create a browser component
            string url = ConfigurationManager.AppSettings["Url"];
            chromeBrowser = new ChromiumWebBrowser(url);

            // Add it to the form and fill it to the form window.
            this.Controls.Add(chromeBrowser);
            chromeBrowser.Dock = DockStyle.Fill;

            // Allow the use of local resources in the browser
            BrowserSettings browserSettings = new BrowserSettings();
            browserSettings.FileAccessFromFileUrls = CefState.Enabled;
            browserSettings.UniversalAccessFromFileUrls = CefState.Enabled;
            browserSettings.WebSecurity = CefState.Enabled;
            chromeBrowser.BrowserSettings = browserSettings;
        }

        private void Form1_FormClosing(object sender, FormClosingEventArgs e)
        {
            Cef.Shutdown();
        }
    }
}

using System.Diagnostics;
using CefSharp.WinForms;
using VR.DAL;
using System;

namespace VR.Winfrom
{
   public class FormProcess
    {
        // Declare a local instance of chromium and the main form in order to execute things from here in the main thread
        private static ChromiumWebBrowser _instanceBrowser = null;
        // The form class needs to be changed according to yours
        private static Form1 _instanceMainForm = null;
        
        public FormProcess(ChromiumWebBrowser originalBrowser, Form1 mainForm)
        {
            _instanceBrowser = originalBrowser;
            _instanceMainForm = mainForm;
        }

        public void opencmd(string filePath)
        {
               
                string file = @"" + filePath;
                ProcessStartInfo start = new ProcessStartInfo(file);
                Process.Start(start);
        }

       
    }
}

<button class="btn btn-primary" onclick="FormProcess.opencmd('C://Program Files (x86)//Google//Chrome//Application//chrome.exe');">Open</button>