How to enumerate all windows belonging to a particular process using .NET?

Question

How i can find all the windows created by a particular process using c#?

UPDATE

i need enumerate all the windows belonging to an particular process using the PID (process ID) of the an application.

Answer 1

Use the Win32 API EnumWindows (if you want child windows EnumChildWindows)), or alternatively you can use EnumThreadWindows .

[DllImport("user32.dll", CharSet=CharSet.Auto, SetLastError=true)]
public static extern bool EnumWindows(EnumThreadWindowsCallback callback, IntPtr extraData);

Then check which process each window belongs to by using the Win32 API GetWindowThreadProcessId

[DllImport("user32.dll", CharSet=CharSet.Auto, SetLastError=true)]
public static extern int GetWindowThreadProcessId(HandleRef handle, out int processId);

Answer 2

delegate bool EnumThreadDelegate(IntPtr hWnd, IntPtr lParam);

[DllImport("user32.dll")]
static extern bool EnumThreadWindows(int dwThreadId, EnumThreadDelegate lpfn, IntPtr lParam);

static IEnumerable<IntPtr> EnumerateProcessWindowHandles(int processId)
{
    var handles = new List<IntPtr>();

    foreach (ProcessThread thread in Process.GetProcessById(processId).Threads)
        EnumThreadWindows(thread.Id, (hWnd, lParam) => { handles.Add(hWnd); return true; }, IntPtr.Zero);

    return handles;
}

and sample usage:

private const uint WM_GETTEXT = 0x000D;

[DllImport("user32.dll", CharSet = CharSet.Auto)]
static extern IntPtr SendMessage(IntPtr hWnd, uint Msg, int wParam, StringBuilder lParam);

[STAThread]
static void Main(string[] args)
{
    foreach (var handle in EnumerateProcessWindowHandles(Process.GetProcessesByName("explorer").First().Id))
    {
        StringBuilder message = new StringBuilder(1000);
        SendMessage(handle, WM_GETTEXT, message.Capacity, message);
        Console.WriteLine(message);
    }
}