https://www.tenforums.com/software-apps/49635-sendkeys-not-working-windows-10-a.html
First of all. The Calculator in Windows 10 is a Universal app, unlike the old calculator. You cannot use SendKeys with it. Nothing you can do will fix that. It has nothing to do with UAC, there simply is no Win32 message passing between Desktop and Universal Apps. Further, Universal apps don't work at all without UAC because they depend on the UAC subsystem to function.
Second of all, some of the stuff you're talking about has very logical reasons for it. For instance, read this:
UAC Architecture
In particular, pay close attention to the Virtualization section.
Finally, Windows does not allow messages to be sent between windows of different privilege. This is to prevent Shatter attacks. It's called User Interface Privilege Isolation.
Shatter attack - Wikipedia, the free encyclopedia
The fact that you don't know ANY of this stuff makes me just shake my head when you sit here yelling about how you know everything, and have nothing to learn. Just amazing.
If you plan to use Windows 10, then i'd suggest giving up on SendKeys. It's not a maintainable solution.
You also don't mention what you're using to do your SendKeys implementation. If you're using .NET (C# or VB.NET) and you aren't trying to send between different privilege contexts, then there is an app.config entry that might help, read the note on the SendKeys class
参考
https://msdn.microsoft.com/en-us/library/system.windows.forms.sendkeys(v=vs.110).aspx
