Example of extracting info from windows on the desktop.

WindowEnumerationExamples.cs

/* -------------------------------------   
  * Produces the output (partial) below
  * Title: .NET-BroadcastEventWindow.4.0.0.0.3719ec0.0 Visible: False Thread: 8632 pid: 6148
  * Title: Microsoft Edge Visible: True Thread: 9172 pid: 8608
  * .... 
*/ ------------------------------------- 

using System;
using System.Collections.Generic;
using System.Runtime.InteropServices;
using System.Text;

namespace ConsoleApp1
{
    internal class Program
    {
        internal static void Main(string[] args)
        {
            StringBuilder stringBuilder = new StringBuilder();
            IEnumerable<IntPtr> hWnds = EnumWindows();

            foreach (IntPtr hWnd in hWnds)
            {
                var text = GetTextFromHwnd(hWnd);
                var isVisible = IsWindowVisible(hWnd);
                var threadIdAndPID = GetThreadAndPIDFromHWND(hWnd);
                stringBuilder.AppendLine(string.IsNullOrEmpty(text) ? "TITLE: UNKNOWN" : $"Title: {text} Visible: {isVisible} Thread: {threadIdAndPID.threadID} pid: {threadIdAndPID.pid}");
            }

            Console.WriteLine(stringBuilder.ToString());
            stringBuilder.Clear();
            Console.ReadLine();
        }

        public static string GetTextFromHwnd(IntPtr hwnd)
        {
            int size = GetWindowTextLength(hwnd);
            if (size++ > 0)
            {
                StringBuilder sb = new StringBuilder(size);
                GetWindowText(hwnd, sb, size);
                return sb.ToString();
            }
            else
            {
                return "";
            }
        }

        public static IEnumerable<IntPtr> EnumWindows()
        {
            IntPtr tempHwnd = FindWindow(null, null);
            List<IntPtr> window = new List<IntPtr>();
            while (tempHwnd != IntPtr.Zero)
            {
                yield return tempHwnd;
                tempHwnd = GetWindow(tempHwnd, GW_HWNDNEXT);
            }
        }

        public static (uint threadID, uint pid) GetThreadAndPIDFromHWND(IntPtr hWnd)
        {
            uint dwThreadId = GetWindowThreadProcessId(hWnd, out uint dwPid);
            return (dwThreadId, dwPid);
        }

        public static (uint threadID, IntPtr hwnd) GetThreadAndHWNDFromPID(int pid)
        {
            IntPtr hwnd = GetTopWindow(IntPtr.Zero);

            while (hwnd != IntPtr.Zero)
            {
                uint dwThreadId = GetWindowThreadProcessId(hwnd, out uint dwPid);

                if (dwPid == pid)
                {
                    return (dwThreadId, hwnd);
                }

                hwnd = GetWindow(hwnd, GW_HWNDNEXT);
            }

            return (0, hwnd);
        }

        private const int GW_HWNDNEXT = 2;

        [DllImport("user32.dll")]
        public static extern bool IsWindowVisible(IntPtr hWnd);

        [DllImport("user32.dll", SetLastError = true)]
        protected static extern uint GetWindowThreadProcessId(IntPtr hWnd, out uint lpdwProcessId);

        protected delegate bool EnumWindowsProc(IntPtr hWnd, IntPtr lParam);

        [DllImport("user32.dll", CharSet = CharSet.Unicode)]
        protected static extern int GetWindowText(IntPtr hWnd, StringBuilder strText, int maxCount);

        [DllImport("user32.dll", CharSet = CharSet.Unicode)]
        protected static extern int GetWindowTextLength(IntPtr hWnd);

        [DllImport("user32.dll")]
        protected static extern IntPtr GetWindow(IntPtr hwndSibling, int wFlag);

        [DllImport("user32.dll")]
        protected static extern IntPtr GetTopWindow(IntPtr hWnd);

        [DllImport("user32.dll", SetLastError = true)]
        protected static extern IntPtr FindWindow(string lpClassName, string lpWindowName);
    }
}