Enumerates Top-Level Windows, Processes, Thread Ids

readme.txt

Source code for an answer corresponding to the following Stack Overflow Question
http://stackoverflow.com/questions/5098994
"C# - user32.dll - GetWindowRect problem"

EnumPTW.cs

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

namespace EnumPTW
{
    class Program
    {
        #region Externs and Associated Things
        [DllImport("user32.dll")]
        static extern bool GetWindowRect(IntPtr hWnd, out RECT lpRect);

        [StructLayout(LayoutKind.Sequential)]
        public struct RECT
        {
            public int Left;        // x position of upper-left corner
            public int Top;         // y position of upper-left corner
            public int Right;       // x position of lower-right corner
            public int Bottom;      // y position of lower-right corner
        }

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

        // Callback Declaration
        public delegate bool EnumWindowsCallback(IntPtr hwnd, int lParam);
        [DllImport("user32.dll")]
        private static extern int EnumWindows(EnumWindowsCallback callPtr, int lParam);

        public static bool ReportWindow(IntPtr hwnd, int lParam)
        {
            uint processId = 0;
            uint threadId = GetWindowThreadProcessId(hwnd, out processId);

            RECT rt = new RECT();
            bool locationLookupSucceeded = GetWindowRect(hwnd, out rt);

            Console.WriteLine(string.Format("Enumerated Window Handle 0x{0:X8}, Process {1}, Thread {2}", hwnd.ToInt32(), processId, threadId));
            if (locationLookupSucceeded)
            {
                Console.WriteLine(string.Format("  Position: {0},{1} through {2},{3}", rt.Left, rt.Top, rt.Right, rt.Bottom));
            }
            else
            {
                Console.WriteLine("  Unable to lookup position through GetWindowRect()");
            }

            try
            {
                Process ownerProcess = Process.GetProcessById((int)processId);
                bool isMainWindow = ownerProcess.MainWindowHandle.Equals(hwnd);
                Console.WriteLine(string.Format("  Process: {0}{1}", ownerProcess.ProcessName, isMainWindow ? " (MainWindow)" : " (Other Window)"));
            }
            catch (Exception ex)
            {
                Console.WriteLine(string.Format("  Unable to lookup Process Information for pid {0}", processId));
                Console.WriteLine(string.Format("    - Exception of type {0} occurred.", ex.GetType().Name));
            }

            return true;
        }
        #endregion//Externs and Associated Things

        static void Main(string[] args)
        {
            // Have to declare a delegate so that a thunk is created, so that win32 may call us back.
            EnumWindowsCallback callBackFn = new EnumWindowsCallback(ReportWindow);

            EnumWindows(callBackFn, 0);

            Console.WriteLine("Finished. Press any key to continue.");
            Console.ReadKey();
        }
    }
}