C# Signature:
[DllImport("user32.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
static extern bool EnumChildWindows(IntPtr hwndParent, EnumWindowsProc lpEnumFunc, IntPtr lParam);
public delegate bool Win32Callback(IntPtr hwnd, IntPtr lParam);
[DllImport("user32.Dll")]
[return: MarshalAs(UnmanagedType.Bool)]
public static extern IntPtr EnumChildWindows(IntPtr parentHandle, Win32Callback callback,IntPtr lParam);
VB Signature:
<DllImport("user32.dll", CharSet:=CharSet.Auto)> _
Private Shared Function EnumChildWindows(ByVal hWndParent As System.IntPtr, _
ByVal lpEnumFunc As EnumWindowsProc, ByVal lParam As Integer) As Boolean
' Leave function empty
End Function
User-Defined Types:
Notes:
The corresponding unmanaged return type is a 4-byte Win32 'BOOL', so mark the method with the MarshalAsAttribute(UnmanagedType.Bool).
Tips & Tricks:
http://www.vbaccelerator.com/home/NET/Code/Libraries/Windows/Enumerating_Windows/article.asp has a nice article
Sample Code:
[DllImport("user32")]
[return: MarshalAs(UnmanagedType.Bool)]
public static extern bool EnumChildWindows(IntPtr window, EnumWindowProc callback, IntPtr i);
/// <summary>
/// Returns a list of child windows
/// </summary>
/// <param name="parent">Parent of the windows to return</param>
/// <returns>List of child windows</returns>
public static List<IntPtr> GetChildWindows(IntPtr parent)
{
List<IntPtr> result = new List<IntPtr>();
GCHandle listHandle = GCHandle.Alloc(result);
try
{
EnumWindowProc childProc = new EnumWindowProc(EnumWindow);
EnumChildWindows(parent, childProc, GCHandle.ToIntPtr(listHandle));
}
finally
{
if (listHandle.IsAllocated)
listHandle.Free();
}
return result;
}
/// <summary>
/// Callback method to be used when enumerating windows.
/// </summary>
/// <param name="handle">Handle of the next window</param>
/// <param name="pointer">Pointer to a GCHandle that holds a reference to the list to fill</param>
/// <returns>True to continue the enumeration, false to bail</returns>
private static bool EnumWindow(IntPtr handle, IntPtr pointer)
{
GCHandle gch = GCHandle.FromIntPtr(pointer);
List<IntPtr> list = gch.Target as List<IntPtr>;
if (list == null)
{
throw new InvalidCastException("GCHandle Target could not be cast as List<IntPtr>");
}
list.Add(handle);
// You can modify this to check to see if you want to cancel the operation, then return a null here
return true;
}
/// <summary>
/// Delegate for the EnumChildWindows method
/// </summary>
/// <param name="hWnd">Window handle</param>
/// <param name="parameter">Caller-defined variable; we use it for a pointer to our list</param>
/// <returns>True to continue enumerating, false to bail.</returns>
public delegate bool EnumWindowProc(IntPtr hWnd, IntPtr parameter);
Alternative Managed API:
The ManagedWindowsApi project (http://mwinapi.sourceforge.net) provides a
method ManagedWinapi.SystemWindow.FilterDescendantWindows().
