[DllImport("user32.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
static extern bool EnumWindows(EnumWindowsProc lpEnumFunc, IntPtr lParam);
Callback EnumWindowsProc should return true to continue enumerating or false to stop.
The corresponding unmanaged return type is a 4-byte Win32 'BOOL', so mark the method with the MarshalAsAttribute(UnmanagedType.Bool).
http://msdn2.microsoft.com/en-us/library/d186xcf0(VS.71).aspx
using System.Runtime.InteropServices;
public delegate bool CallBackPtr(int hwnd, int lParam);
public class EnumReport
{
[DllImport("user32.dll")]
public static extern int EnumWindows(CallBackPtr callPtr, int lPar);
public static bool Report(int hwnd, int lParam)
{
Console.WriteLine("Window handle is "+hwnd);
return true;
}
}
static void Main()
{
CallBackPtr callBackPtr = new CallBackPtr(EnumReport.Report);
EnumReport.EnumWindows(callBackPtr, 0);
}
The ManagedWindowsApi project (http://mwinapi.sourceforge.net) provides a static
method ManagedWinapi.SystemWindow.FilterToplevelWindows().