How to get main window handle from process id?


How to get main window handle from process id?

I want to bring this window to the front.

It works well in "Process Explorer".

12/11/2009 3:48:49 PM

I checked how .NET determines the main window.

My finding showed that it also uses EnumWindows().

This code should do it similarly to the .NET way:

struct handle_data {
    unsigned long process_id;
    HWND window_handle;

HWND find_main_window(unsigned long process_id)
    handle_data data;
    data.process_id = process_id;
    data.window_handle = 0;
    EnumWindows(enum_windows_callback, (LPARAM)&data);
    return data.window_handle;

BOOL CALLBACK enum_windows_callback(HWND handle, LPARAM lParam)
    handle_data& data = *(handle_data*)lParam;
    unsigned long process_id = 0;
    GetWindowThreadProcessId(handle, &process_id);
    if (data.process_id != process_id || !is_main_window(handle))
        return TRUE;
    data.window_handle = handle;
    return FALSE;   

BOOL is_main_window(HWND handle)
    return GetWindow(handle, GW_OWNER) == (HWND)0 && IsWindowVisible(handle);
7/21/2018 5:23:04 AM

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