SendMessage PostMessage ( hWnd, Msg, wParam, lParam) 四个参数是如何定义的，

ref:

https://blog.csdn.net/mcw_720624/article/details/117192221?spm=1001.2101.3001.6650.1&utm_medium=distribute.pc_relevant.none-task-blog-2%7Edefault%7ECTRLIST%7ERate-1.pc_relevant_antiscanv2&depth_1-utm_source=distribute.pc_relevant.none-task-blog-2%7Edefault%7ECTRLIST%7ERate-1.pc_relevant_antiscanv2&utm_relevant_index=2

https://docs.microsoft.com/en-us/windows/win32/winmsg/about-messages-and-message-queues

 

ref: !!! C#-windows学习笔记续键盘输入.doc_人人文库网.html

https://www.renrendoc.com/p-59592430.html

WM_KEYDOWN
SendMessage( hWnd, Msg, wParam, lParam) 第四个参数是自由微软定义的，
ref: 《Windows API 函数SendMessage与PostMessage使用方法和常见的坑》
https://blog.csdn.net/mcw_720624/article/details/117192221?spm=1001.2101.3001.6650.1&utm_medium=distribute.pc_relevant.none-task-blog-2%7Edefault%7ECTRLIST%7ERate-1.pc_relevant_antiscanv2&depth_1-utm_source=distribute.pc_relevant.none-task-blog-2%7Edefault%7ECTRLIST%7ERate-1.pc_relevant_antiscanv2&utm_relevant_index=2
WM_KEYDOWN就要使用 0 ，WM_KEYUP 就要用1。这个最容易把人搞迷糊，我怎么知道什么消息要对应什么参数呢？
别急，在MSDN上能查的到https://docs.microsoft.com/zh-cn/windows/win32/api/winuser/nf-winuser-sendmessage。只不过是英文的，