How can I get the child windows of a window given its HWND?

Question

I have the handle for a given window. How can I enumerate its child windows?

Answer 1

Here you have a working solution:

public class WindowHandleInfo {     private delegate bool EnumWindowProc(IntPtr hwnd, IntPtr lParam);      [DllImport("user32")]     [return: MarshalAs(UnmanagedType.Bool)]     private static extern bool EnumChildWindows(IntPtr window, EnumWindowProc callback, IntPtr lParam);      private IntPtr _MainHandle;      public WindowHandleInfo(IntPtr handle)     {         this._MainHandle = handle;     }      public List<IntPtr> GetAllChildHandles()     {         List<IntPtr> childHandles = new List<IntPtr>();          GCHandle gcChildhandlesList = GCHandle.Alloc(childHandles);         IntPtr pointerChildHandlesList = GCHandle.ToIntPtr(gcChildhandlesList);          try         {             EnumWindowProc childProc = new EnumWindowProc(EnumWindow);             EnumChildWindows(this._MainHandle, childProc, pointerChildHandlesList);         }         finally         {             gcChildhandlesList.Free();         }          return childHandles;     }      private bool EnumWindow(IntPtr hWnd, IntPtr lParam)     {         GCHandle gcChildhandlesList = GCHandle.FromIntPtr(lParam);          if (gcChildhandlesList == null || gcChildhandlesList.Target == null)         {             return false;         }          List<IntPtr> childHandles = gcChildhandlesList.Target as List<IntPtr>;         childHandles.Add(hWnd);          return true;     } } 

How to consume it:

class Program {     [DllImport("user32.dll", EntryPoint = "FindWindowEx")]     public static extern IntPtr FindWindowEx(IntPtr hwndParent, IntPtr hwndChildAfter, string lpszClass, string lpszWindow);      static void Main(string[] args)     {         Process[] anotherApps = Process.GetProcessesByName("AnotherApp");         if (anotherApps.Length == 0) return;         if (anotherApps[0] != null)         {             var allChildWindows = new WindowHandleInfo(anotherApps[0].MainWindowHandle).GetAllChildHandles();         }     } } 

Answer 2

Using:

internal delegate int WindowEnumProc(IntPtr hwnd, IntPtr lparam);  [DllImport("user32.dll")] internal static extern bool EnumChildWindows(IntPtr hwnd, WindowEnumProc func, IntPtr lParam); 

you will get callbacks on the function you pass in.