BrendanMcK wonderfully respond to my question on this post:
Setting up Hook on Windows messages
I copied his answer just below. It is more convenient than Timer as I suggered, and it is less CPU-eater than UIAutomation. Thanks everyone!
using System;
using System.Windows;
using System.Windows.Forms;
using System.Runtime.InteropServices;
class NameChangeTracker
{
delegate void WinEventDelegate(IntPtr hWinEventHook, uint eventType,
IntPtr hwnd, int idObject, int idChild, uint dwEventThread, uint dwmsEventTime);
[DllImport("user32.dll")]
static extern IntPtr SetWinEventHook(uint eventMin, uint eventMax, IntPtr
hmodWinEventProc, WinEventDelegate lpfnWinEventProc, uint idProcess,
uint idThread, uint dwFlags);
[DllImport("user32.dll")]
static extern bool UnhookWinEvent(IntPtr hWinEventHook);
const uint EVENT_OBJECT_NAMECHANGE = 0x800C;
const uint WINEVENT_OUTOFCONTEXT = 0;
// Need to ensure delegate is not collected while we're using it,
// storing it in a class field is simplest way to do this.
static WinEventDelegate procDelegate = new WinEventDelegate(WinEventProc);
public static void Main()
{
// Listen for name change changes across all processes/threads on current desktop...
IntPtr hhook = SetWinEventHook(EVENT_OBJECT_NAMECHANGE, EVENT_OBJECT_NAMECHANGE, IntPtr.Zero,
procDelegate, 0, 0, WINEVENT_OUTOFCONTEXT);
// MessageBox provides the necessary mesage loop that SetWinEventHook requires.
// In real-world code, use a regular message loop (GetMessage/TranslateMessage/
// DispatchMessage etc or equivalent.)
MessageBox.Show("Tracking name changes on HWNDs, close message box to exit.");
UnhookWinEvent(hhook);
}
static void WinEventProc(IntPtr hWinEventHook, uint eventType,
IntPtr hwnd, int idObject, int idChild, uint dwEventThread, uint dwmsEventTime)
{
// filter out non-HWND namechanges... (eg. items within a listbox)
if(idObject != 0 || idChild != 0)
{
return;
}
Console.WriteLine("Text of hwnd changed {0:x8}", hwnd.ToInt32());
}
}