How to Get the Main Window Handle Using a Process ID?

How to Retrieve the Main Window Handle Using Process ID:

To retrieve the main window handle of a process, you can employ the following steps:

1. Utilize the EnumWindows() function to enumerate all top-level windows in the system.
2. Within the callback function enum_windows_callback(), check if the process ID associated with the current window matches the target process ID.
3. If a match is found, determine if the current window is a main window by verifying that it has no owner (GetWindow(handle, GW_OWNER) == (HWND)0) and is visible (IsWindowVisible(handle) == TRUE).
4. Upon identifying the main window, store its handle in the handle_data structure and return FALSE to stop the enumeration.

Here's an example code that implements these steps:

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);
}

The above is the detailed content of How to Get the Main Window Handle Using a Process ID?. For more information, please follow other related articles on the PHP Chinese website!