C# how to get current url of Firefox

Question

I'm creating a C# application to get the Firefox current url.

I have tested many algorithms, but they did not work.

I have tried this links:

Getting the current tab's URL from Google Chrome using C#

https://hintdesk.com/2011/09/02/c-list-all-opened-tabs-of-firefox-with-uiautomation/

And tried this script also (not working!!!):

DdeClient dde = new DdeClient(browser, "WWW_GetWindowInfo");
dde.Connect();
string url = dde.Request("URL", int.MaxValue);
string[] text = url.Split(new string[] { "\",\"" }, StringSplitOptions.RemoveEmptyEntries);
dde.Disconnect();
return text[0].Substring(1);