让 Win32 MessageBox 出现在其他程序之上

Question

I've recently started learning Python and wrote a little script that informs me when a certain website changes content. I then added it as a scheduled task to Windows so it can run every 10 minutes. I'd like to be informed of the website changing right away so I added a win32ui MessageBox that pops up if the script detects that the website has changed. Here's the little code snippet I'm using for the MessageBox (imaginative text, I know):

win32ui.MessageBox("The website has changed.", "Website Change", 0)

My issue is this, I spend most of my time using remote desktop so when the MessageBox does pop up it sits behind the remote desktop session, is there any way to force the MessageBox to appear on top of it?

On a similar note when the script runs the command line opens up very briefly over the remote desktop session which I don't want, is there any way of stopping this behaviour?

I'm happy with Windows specific solutions as I'm aware it might mean dealing with the windowing manager or possibly an alternative way to inform me rather than using a MessageBox.

Answer 1

When you start anything from Task Scheduler, Windows blocks any " easy " ways to bring your windows or dialogs to top.

1. First way - use MB_SYSTEMMODAL (4096 value) flag. In my experience, it makes Msg dialog "Always on top".

    win32ui.MessageBox("The website has changed.", "Website Change", MB_SYSTEMMODAL)

2. Second way - try to bring your console/window/dialog to the front with Following calls. Of course, if you use MessageBox you must do that (for your own created window) before calling MessageBox .

    SetForegroundWindow(Wnd); BringWindowToTop(Wnd); SetForegroundWindow(Wnd);

As for flickering of the console window, you may try to start Python in a hidden state. For example, use ConEmu , 'HidCon' or cmdow . Refer to their parameters, something like:

ConEmu -basic -MinTSA -cmd C:\Python27\python.exe C:\pythonScript.py
    or
CMDOW /RUN /MIN C:\Python27\python.exe C:\pythonScript.py

Answer 2

Avoiding the command window flash is done by naming the script with a pyw extension instead of simply py . You might also use pythonw.exe instead of python.exe , it really depends on your requirements.

See http://onlamp.com/pub/a/python/excerpts/chpt20/index.html?page=2

Answer 3

Use ctypes it displays an windows error message box very easy to use,

import ctypes
if condition:
    ctypes.windll.user32.MessageBoxW(0, u"Error", u"Error", 0)

Answer 4

This works for me:

from ctypes import *
def MessageBox(title, text, style):
    sty = int(style) + 4096
    return windll.user32.MessageBoxW(0, text, title, sty) #MB_SYSTEMMODAL==4096
    ## Button Styles:
    ###  0:OK  --  1:OK|Cancel -- 2:Abort|Retry|Ignore -- 3:Yes|No|Cancel -- 4:Yes|No -- 5:Retry|No -- 6:Cancel|Try Again|Continue
    ## To also change icon, add these values to previous number
    ### 16 Stop-sign  ### 32 Question-mark  ### 48 Exclamation-point  ### 64 Information-sign ('i' in a circle)

Usage:

MessageBox('Here is my Title', 'Message to be displayed', 64)

Answer 5

Making the message box system modal will cause it to pop up over every application, but none can be interacted with until it is dismissed. Consider either creating a custom dialog box window that you can bring to the front or using a notification bubble instead.

Answer 6

Windows tries to make it hard to pop a window over the active application. Users find it annoying, especially since the interrupting window generally steals keyboard focus.

The Windows way to give a notification like this is with a balloon in the notification area rather than a message box. Notification balloons don't steal focus and are (supposedly) less distracting.

I'm not sure if the python Windows UI library offers wrappers for notification balloons .

Answer 7

Very easy modal async message box with help of Python and MSG command (working on Win10):

# In CMD (you may use Username logged on target machine instead of * to send message to particular user):
msg /server:IP_or_ComputerName * /v /time:appearance_in_secs Message_up_to_255_chars 
# I.e. send "Hello everybody!" to all users on 192.168.0.110 disappearing after 5 mins 
msg /server:192.168.0.110 * /v /time:300 "Hello everybody!"

In Python I've been using subprocess to send CMD commands, allows me to read and process output, find error etc.

import subprocess as sp

name = 'Lucas'
message = f'Express yourself {name} in 255 characters ;)'
command = f'msg /server:192.168.0.110 * /v /time:360 "{message}"'
output = str(sp.run(command, stdout=subprocess.PIPE, stderr=subprocess.STDOUT))

if 'returncode=0' in output:
    pint('Message sent')
else:
    print('Error occurred. Details:\n')
    print(output[output.index('stdout=b'):])