Need help with a C# Project

In a very simple C# Windows Form .NET Framework project in Visual Studio 2019 I have one form with the CefSharp browser. This browser shows a fixed intranet website. I need 2 things. 1. A whitelist, to prevent visiting other websites. 2. A custom Protocol Execution handler class. Based on the class displayed below. (I need to open an local MS Office file by clicking a href link). public class CustomRequestHandler : [login to view URL] { protected override bool OnBeforeBrowse(IWebBrowser chromiumWebBrowser, IBrowser browser, IFrame frame, IRequest request, bool userGesture, bool isRedirect) { proceeding. if ([login to view URL]("customScheme:")) { [login to view URL]([login to view URL]); return true; } return [login to view URL](chromiumWebBrowser, browser, frame, request, userGesture, isRedirect); } } [login to view URL] = new CustomRequestHandler();