自动登录电脑版微信给指定用户发送消息的python代码，需要先安装uiautomation库，同时要按实际情况修改微信程序的安装目录，设定收信用户名和要发送的消息。注意：不改变原来在电脑上登录微信的安全验证，如需要扫码、需要手机确认等。

# -*- coding:utf-8 -*-
 
import psutil  # 要额外安装，判断程序是否运行
from time import sleep
import uiautomation  # 要额外安装，操控窗口控件
import os
 
 
def ifProcessRunning(process_name='WeChat.exe'):
    # 判断某个程序是否在运行
    # 原理：获取正在运行程序的pid，通过pid获取程序名，再按程序名进行判断
    pl = psutil.pids()
    result = "PROCESS_IS_NOT_RUNNING"
    for pid in pl:
        if (psutil.Process(pid).name() == process_name):
            if isinstance(pid, int):
                result = "PROCESS_IS_RUNNING"
    return result
 
 
def wechatlogin():
    uiautomation.uiautomation.TIME_OUT_SECOND = 2  # global time out
    if ifProcessRunning()=="PROCESS_IS_RUNNING":
        try:
            wechatWindow = uiautomation.WindowControl(searchDepth=1, className='WeChatMainWndForPC', Name='微信')
            wechatWindow.Restore()
            wechatWindow.Minimize()
        except:
            try:
                uiautomation.PaneControl(searchDepth=1, ClassName='WeChatLoginWndForPC', Name='微信').ButtonControl(Name='仅传输文件')
            except:
                pass
            os.system('taskkill /F /im "WeChat.exe" >nul')
            os.startfile(WeChat_path)
            loginwin = uiautomation.PaneControl(searchDepth=1, ClassName='WeChatLoginWndForPC', Name='微信')
            try:
                loginwin.ButtonControl(Name='进入微信').Click()
            except:
                loginwin.ButtonControl(Name='登录').Click()
    else:
        os.startfile(WeChat_path)
        loginwin = uiautomation.PaneControl(searchDepth=1, ClassName='WeChatLoginWndForPC', Name='微信')
        try:
            loginwin.ButtonControl(Name='进入微信').Click()
        except:
            loginwin.ButtonControl(Name='登录').Click()
    uiautomation.uiautomation.TIME_OUT_SECOND = 20  # global time out
    wechatWindow = uiautomation.WindowControl(searchDepth=1, className='WeChatMainWndForPC', Name='微信')
    sleep(10)
    try:
        wechatWindow.Minimize()
    except:
        pass
 
 
def wechatmsg(send_to='微信用户名',msg='要发送的消息'):
    uiautomation.uiautomation.TIME_OUT_SECOND = 20
    wechatWindow = uiautomation.WindowControl(searchDepth=1, className='WeChatMainWndForPC', Name='微信')
    try:
        wechatWindow.Restore()
    except:
        pass
    wechatWindow.MoveToCenter()
    wechatWindow.SetTopmost(True)
    # sleep(2)
    wechatWindow.EditControl(Name="搜索").Click()
    wechatWindow.EditControl(Name="搜索").SendKeys(f'{send_to}{{enter}}', 0.5)
    wechatWindow.EditControl(Name=send_to).SendKeys(msg,0.03)
    wechatWindow.ButtonControl(Name="发送(S)").Click()
    wechatWindow.SetTopmost(False)
    wechatWindow.Minimize()
 
def wechatquit():
    if ifProcessRunning()=="PROCESS_IS_RUNNING":
        os.system('taskkill /F /im "WeChat.exe" >nul')
 
if __name__ == '__main__':
    WeChat_directory = 'D:\soft\WeChat'
    WeChat_path= os.path.join(WeChat_directory, 'WeChat.exe')
    wechatlogin()
    wechatmsg(send_to='微信收信用户名张三',msg='要发送的消息')
    wechatmsg(send_to='李四', msg='要发送的消息')
    # wechatquit()